Into The Breach
by 29Pieces
Summary: What if in Cas's first trip through the rift, he didn't meet Bobby, but his own counterpart? What if the wrong Castiel came back through the portal, and our Cas ended up trapped on the other side with Mary and Lucifer? How will they survive this terrifying world and find their way home? S12 AU/alternate ending, co-written with Aini NuFire
1. Seeing What Might Have Been

_A/N: Hello and welcome to the first collaborative work of Aini NuFire and I! This fic is for amycooper on AO3, as she's the one who pitched the idea to Aini on her Tumblr page. ****Season 12 finale spoilers**** She wanted a fic where the boys THINK Cas is dead, but really he and Mary are struggling to survive in the alt!Universe. If you haven't seen the season 12 finale yet, this does contain spoilers. A lot of dialogue is lifted from that episode. And on that note, standard disclaimers apply, neither of us own the canon SPN characters. _

_We'll be updating here and on AO3 on Wednesdays and Sundays._

 _I hope you all enjoy this as much as we enjoyed working together on it!_ _So... let's jump right in ;)_

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 **Chapter 1 - Seeing What Might Have Been**

The clock was counting down. It was only a matter of days at this point. Castiel stepped outside to do a perimeter check of the small, secluded house he and Kelly had sequestered themselves away in. Even though it was heavily warded, Castiel knew he couldn't let his guard down.

All seemed quiet at the lake house as he descended the back porch steps; it was always tranquil out here. But then a flicker of gold caught Castiel's eye, and he frowned at the glowing fault line suspended in the air halfway between the house and the water front. His brow furrowed as he made his way toward it. That had not been there this morning, he was certain.

He walked a half circle around the energy displacement, which hung like a fizzling thread, one foot above the ground, and itself five feet in length. Castiel's frown deepened as he studied the strange phenomenon. Where could it have come from? And what was it, precisely? As far as he could tell, it wasn't _doing_ anything, per se. But cracks of dormant plasma didn't just pop up out of nowhere.

Castiel raised a finger toward it cautiously. The air along the disturbance sizzled, and the instant Castiel touched the simmering edge, he was sucked into a whirling vortex. It spat him out a split second later into a dusty, barren wasteland. Castiel staggered to regain his balance, chest heaving as his vessel's lungs worked to replenish their oxygen levels. The air was thick with smoke oozing from several mounds of sulfurous earth. Everything was dark, save for the flashes of crimson high above behind a cloud-covered sky, igniting everything in a fulvous glow.

"What…" Castiel stumbled in a circle, unable to orient himself in this nightmarish landscape. There were bodies everywhere. Some fresh kills, some nothing but desiccated remains in disintegrated rags. Strange columns rose from the ground into pointed pillars, like the skeletal remnants of a once significant monument. The crack and rumble of lightning and thunder was a constant echo in the skies, the heavens a broiling brume of fire and brimstone.

A snarl sounded behind him, and Castiel whirled as a figure came launching over a mound of dirt. His heart leaped into his throat as he recognized a denizen of Hell, bearing a guise more likely to be seen _in_ the Pit, not out. Horns sprouted from its forehead to accompany the black eyes.

Before Castiel could draw his blade, the demon had swung an arm so hard that it knocked Castiel to the ground. With an animalistic roar, it raised a clawed hand to strike. Castiel threw his arms up.

A sharp report cracked the air, and the demon jerked. Eyes flew wide as ocher light flashed through its body, and then it fell to the ground with a thud. Castiel looked up at his would-be rescuer, and froze.

Black boots took measured steps toward him, stopping a few feet away. Castiel propped himself up on his elbows and tracked his gaze up the dark jeans and the black leather jacket, which had a simple, militaristic style with buttons all down the left side. Even the top flap was buttoned across the chest severely. Castiel briefly took in the automatic handgun angled down at him, and finally looked up into the stern face gazing back at him.

He was looking at… _himself_. Jimmy Novak's vessel was unmistakable, but so was the glint of grace churning beneath hard blue eyes.

"You?" Castiel uttered.

His counterpart looked him up and down with equal measures of confusion and suspicion. Then he glanced at the glowing gold crack in the air several feet away. After a long beat, he lowered his gun and returned it to the holster on his hip.

"I take it that's a tear in time and space," he finally spoke, and Castiel found it jarring to hear his own voice. Particularly because there was a slightly different tone to it…straightforward and stoic, as Castiel used to be, but this version of himself seemed to…hold himself more confidently, more authoritatively.

Castiel slowly picked himself up off the ground. "It appears so," he said cautiously, and looked around again. The night sky flickered with blood-tinged lightning again, and Castiel's heart clenched with fear. "What is this place?"

"Earth, of course," his counterpart replied, taking a few steps around the back of the rift to examine it.

"But…what _happened_?" Castiel breathed.

This alternate version of him came back around and gave him a confused look. "The End." His brow furrowed, and he roved his gaze up and down Castiel again. "Has the Apocalypse not started in your reality?"

"Yes, it did, but…" He threw another bewildered look around this Hell on Earth. "But we stopped it." He turned back to his alternate. "Where are the Winchesters?"

"Who?"

"Sam and Dean Winchester," Castiel pressed. "In my world, they stopped the Apocalypse from happening." Dread seized his lungs and squeezed. "Did- did they say 'yes' in this world?"

His counterpart regarded him with a flicker of impatience. "I have no idea what you're talking about. Heaven and Hell are locked in eternal war, with Earth as the primary battlefield."

"But what about Michael and Lucifer's true vessels? The Righteous Man who broke the First Seal!"

"John Winchester was rescued from Hell and became Michael's vessel, yes."

Castiel's eyes widened. _What?_ "What about his sons?"

His alternate quirked a perplexed brow at him. "John Winchester had no children." He then shook his head in mounting irritation. "Look, my world has enough problems to deal with, in case you didn't notice. And now this?" He gestured sharply at the glowing rip in reality. "We need to fix it, before it tears _both_ our worlds asunder."

Castiel stiffened guiltily. He had a good inclination as to what had caused this. "It should only be temporary," he said.

His alternate narrowed his eyes. "You know what caused it?"

"Um…" Castiel shifted his weight. "A nephilim is about to be born. I suspect that some of the celestial energy surrounding him has leaked out and created…this." He waved helplessly at the portal.

His counterpart's eyes widened in alarm. "A nephilim?"

"Yes. But once he's born, he'll repair the rift. And it'll be soon, so as long as no one discovers this and comes through—"

"You're _allowing_ the abomination to be born?" His alternate suddenly looked on him with horror. "Is it yours?"

"No!" Castiel protested automatically. He gave himself a small shake. "No. But I promised I would take care of him."

"Are you trying to destroy your world?" his counterpart spat in disgust. "What, one Apocalypse wasn't enough for you?"

Castiel bristled. "This child isn't evil. He's shown me a vision of the future, one where he brings peace to the world. No more fighting, no more hate, or pain."

His alternate's expression hardened. "That seems unlikely."

Castiel lifted his chin. "I have faith."

His opposite let out a derisive snort. "Fine. It's your world's fate on the line." He flicked a look at the rent in space. "You're certain this nephilim will repair the rift? And soon?"

"Yes," Castiel assured him.

"He'd better. I was nearby when I sensed the energy disturbance, but you can bet it won't be long before other angels or demons discover it, too."

Castiel tensed, and cast a wary look around the area. It seemed deserted, for the most part. But there were fresh kills, which suggested people did traverse the vicinity. "The tear on my side is out of the way from anyone, so there won't be any crossover from my world."

His counterpart gave him a detached, considering look. "I'll see about keeping trespassers out on this side." He turned to start walking away, only to pause and look over his shoulder. "But I have my own people to protect. I don't have time to save yours when you're the one who endangered them in the first place." With that, he strode away into the night under a sky roiling with blood.

Castiel cast one last look around this hellish reality, stomach clenching, before he hurried back through the portal to his own world, a world he believed he could still save.

The frayed ends of his thoughts twisted and wormed their way through the angel's mind, catching on the raw edges of his nerves the way the riptides of the portal flung him back through to the other side. A light shudder trickled through him, leaving Castiel to wish he had more than just an old trench coat for comfort.

"Cas? Cas?"

Castiel gave himself a shake as he heard Kelly calling for him from within the house. There was no point in dwelling on what had never been… not here, anyway.

His concerns were quickly overtaken when he hurried back inside and realized that Kelly was going into labor. Castiel forced himself to stay calm; this was what it had always been leading up to, after all. Kelly was counting on him to keep it together.

"Kelly, it's alright. I'm here," Castiel soothed as he helped her back toward bed. The electricity crackled, heralding the approaching hour, but still the angel tried to school his features to show nothing but reassurance.

"Oh my god," Kelly groaned. "Oh, god."

"Everything's going to be fine," Castiel assured her. The lie he'd learned from the humans rolled off his tongue with ease, almost without thought.

Once there, Castiel helped the woman ease herself down onto the bed, taking great care to prop the pillow up behind her in a way that she would be as comfortable as possible while they waited. _As they waited for her to die_ , Castiel couldn't help but think with a touch of sadness for the human's inevitable fate. He wished there was a way he might save her, after the delivery, but the angel knew it was a futile thought. There was no surviving this.

Still, Castiel would at least do what he could for her while there was still time. Kelly smiled at him as he fussed about adjusting the pillow behind her and the blanket she was lying on, and flicked on the bedside lamp.

Kelly's eyes turned away, a silence falling over the tiny room. Castiel couldn't imagine what she might be going through, but her determination to see it through was astounding to the angel. Put her in flannel, he suddenly thought, and she might have been a Winchester.

Except Dean and Sam would have never chosen this. Castiel's heart clenched, remembering the last time he had seen his friends, and he forced his mind back to the present.

Walking to the window, careful not to let Kelly see past him, Castiel pulled the curtains aside enough to check on the glowing rift in the yard. The visible reminder of the _other place_ sent a chill whispering down his spine and the angel suppressed a shudder.

"Cas?" Kelly spoke up softly from the bed.

He turned, relieved to see her smile again, albeit sadly.

"Thank you," she murmured. "For everything."

"Of course."

They fell into another silence, broken only by Kelly's increasingly tortured breaths. Castiel alternated between sitting by her side and holding her hand, and going to check out the window. The rift continued to dance, the fiery crack seeming to grow bolder as nighttime fell, but otherwise remained unchanged.

The sooner this was over with, the better.

A ragged whimper from the bed brought Castiel immediately back to Kelly's side, resuming his place by the bed. Her exhale turned into a shaky cry as she grabbed the angel's hand, eyes squeezed tightly shut.

"Kelly," he murmured, heavy with worry.

"Tell me again," she whispered. "Tell me again what you saw."

She was clinging to it for hope, the angel realized, a touch of desperation starting to creep into his heart. He nevertheless maintained his calm. "Right, I saw- I saw…" But how could he put it into words? Castiel shook his head and closed his eyes. "I saw the future. I saw a world without pain or hunger or want. I saw the world that this child- that _your_ child will create."

Kelly nodded hopefully, almost pleadingly, urging him on.

"And it is a world without fear and without suffering and without hate." The world he had always wished for these beautiful humans… the world he would have done anything to bless them with. Castiel's heart clenched as he met Kelly's gaze and finished, "I saw paradise."

She nodded, breath hitching as her eyes flooded with tears. The nearby floor lamp crackled again, drawing their attention. Not much longer now…

Alert as Castiel was for any sound of trouble, the noise of an approaching car made him shift immediately. He twisted on the bed, frowning as Kelly jerked away in fear and gasped with pain and alarm. The angel rose to his feet and hurried out of the room and down the stairs, blade already in hand. If anyone had come to do Kelly harm…

But when the front door of the little house opened, Castiel's breath hitched, eyes widening.

"Dean?"

And not just Dean… Sam and even Mary filed in behind him, all wearing matching expressions of worry. Castiel remained guarded, not sure what to expect. He knew the Winchesters did not approve of his mission here. Yet their eyes burned with concern, not animosity.

"Cas, is this place warded?" Sam demanded, foregoing a standard greeting as he pushed forward.

"Yes, heavily."

"Heavy enough to stop Lucifer?" Dean pressed.

Castiel blinked incredulously. " _Lucifer_?"

"He could be right behind us," Mary explained, but that just wasn't possible. It _couldn't_ be possible.

"I don't- what are you doing here?" the angel asked. He'd deal with the Lucifer thing in a minute.

"Saving your ass," snapped Dean.

"Look," Sam picked up, soft but intense. "You and Kelly just taking off was a stupid move. But there's no way we're letting Lucifer get his hands on that kid. It ain't happening."

Neither was Castiel. He felt himself reeling, though; he'd been prepared to fight off demons, angels, even hunters—he didn't dare let himself think the word "Winchesters"—but how was he supposed to hold back the _Devil_ if he came?

"Look, Sam's right, okay?" Dean growled when Castiel was unable to reply. "We'll work through our crap. We always do. But right now, we are here to get you, get Kelly, and get gone."

"She can't be moved," Castiel immediately retorted in consternation. For better or worse, this was where they would have to make a stand. "She's having a-"

He didn't even have to finish, not with the agonized, strangled cry emanating from the upstairs bedroom. All three Winchesters raised their eyes to the ceiling, the boys with a touch of panic, and Mary with resignation.

"I'll check on her," the woman murmured, hurrying past Castiel.

The angel didn't try to stop her, sensing no hidden intentions. Besides, Mary was probably better equipped to offer comfort than Castiel, having already endured these pains twice herself.

Turning back to the boys, Castiel demanded, "How much time do we have?" The better question was, how the _hell_ could Lucifer even be free of the Cage? But that would have to wait until he had ascertained the immediate danger.

"We don't know," Sam admitted.

"Hey," Dean jumped in before Castiel could ask any further question. "If he shows, can you flame on again?"

Flame on…? Castiel stared at the hunter blankly, who clarified with a hint of impatience,

"Can you torch Lucifer like you did Dagon?"

"I don't know-" Castiel started, still trying to catch up. He gave himself a shake. "No," he clarified. "That wasn't me. That was the child. And in case you haven't noticed, he's a little busy." Just a small matter of preparing to enter this world.

Rather than throwing back a retort at Castiel's sharp tone, Dean instead growled in pain and leaned over to clutch his knee. "Son of a bitch," the hunter grumbled, face taut and drawn.

Castiel sighed, rolling his eyes heavenward. What exactly had the human been doing now? What had happened to his leg? Whatever it was, no amount of frustration or impatience could allow the angel to let his friend keep hurting. He stowed his blade away and stepped forward.

"Here, Dean," he muttered. "Let me."

Two fingers to Dean's forehead, a light golden glow with a high, angelic ring, and Dean dropped his foot back down to the floor with a thud.

"Whoa," the hunter murmured, expression clearing into a ghost of a smile. He chuckled. "Thanks."

In spite of the dire situation they were faced with, Castiel felt his heart lighten ever so slightly. They were still friends, then. With everything else shrouded in uncertainty, that...gave him something to hold onto.

"Alright," Sam cut in, already turning. "We should double-check the warding."

Still reeling from the news about Lucifer, it took Castiel a second to realize that the hunters were on their way out the back door… and what they would find just beyond it. He straightened, eyes widening with alarm.

"Wait!"

"Right, so listen, if we, uh…" Sam slowed to a halt on the back steps, gaze fixed on the crackling, glowing rift that pulsed in the darkness outside.

The angel winced, mind already scrambling for answers to the questions his friends were sure to have. He didn't want to lie to them, but neither was he eager for the Winchesters to put themselves through the pain of what he himself had already investigated. Castiel didn't even want to think about that place again, much less discuss it, since it would soon be moot anyway.

"Cas?" Sam hesitated as Dean pushed his way out the back door as well. "What is that?"

"It's a… tear in space and time," Castiel finally answered, settling on the truth.

"Uh, and that means?" Dean demanded, following behind the angel as Castiel stepped down to the yard and approached the split.

"It's a doorway to another world."

"R-right," Sam murmured. A tense hush descended, and Castiel hoped neither would press for the obvious follow-up question, but he should have known Sam would be too sharp. "Wait… Cas, how did this get here?"

No sense in hiding the truth at this point. Surely they had already guessed.

"Well, the child being born," the angel explained, watching the rift with wary foreboding. "His power, it seems to be puncturing the fabric of our universe."

"Awesome," Dean grumbled.

Sam still sounded hesitant, as though he instinctively knew to tread carefully, as he asked, "And… what exactly is on the other side?"

"You don't want to know."

"Probably," Dean said, before heaving a heavy sigh. Castiel could hear the resignation as the hunter finished, "But we need to."

The angel hid his dismay, knowing that the Winchesters wouldn't be satisfied until they had seen for themselves. And… perhaps it was better that way, in spite of Castiel's reluctance. Perhaps they _should_ be witness to it, to fully understand just how terrible the stakes had always been, to recognize just how important their contribution to existence truly was. Castiel could give them that much.

Even still, it was with great reluctance that the angel stepped fully up to the rift and regarded the hovering line of plasma. He paused, steeling himself, then reached a tentative hand to touch the rift, pulling the three of them through.


	2. Steel Your Heart for What Must Be

_A/N: Thank you guest Loreley for your review :)_

 _More dialogue lifted from 12x23 here._

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 **Chapter 2 - Steel Your Heart for What Must Be**

The barren, storm-struck landscape of the alternate world had yet to change much since Castiel's previous trip, save that dawn apparently still came to this universe. Except that 'daylight' brought a pasty gray tinge to everything, the sun hidden behind the thick, cloying atmosphere that still rattled and rumbled with bursts of crimson electricity. Though Castiel was prepared to defend his friends at the first sign of another demon, there were no signs of life… in fact, there was nothing at all but the corpses still lying in haphazard heaps. He saw no sign of his double, for which Castiel was oddly glad.

"Whoa," Sam whispered, audibly shaken. "Cas, what is this?"

"As I said, it's- it's Earth," he replied, ignoring the chill racing down his spine once more. Wanting nothing more than to get back to their own world, the angel explained the little he knew, leaving out the fact that the information had come from… himself.

But yet again, Sam was too sharp with the right questions.

"How do you know all this?" he demanded, leaving Castiel to once again waver between lies or truth.

Finally, he hedged, "A friend told me."

"Oh, good," Dean snapped. "Now you're making friends? That's-" He trailed off, turning a slow circle and taking in a bolstering breath. Though he seemed calm, a muscle was ticking in his jaw and his fingers were twitching with obvious unease. "Alright, on a scale of one to ten, how bad is this?"

Sam snorted and took a step forward. "I don't know. I gotta say, a, uh… hole in reality to a bombed out Apocalypse world? I'm gonna go with eleven."

"Sounds right."

Though Castiel privately had to concur, he shook his head and stepped forward against the rumble of thunder and flash of red-tinged lightning. "You don't have to worry," he assured them, as though he hadn't already been doing exactly that. "The child, he opened this door. He'll close it."

"You sure about that?" Dean asked, ever the skeptic.

Castiel raised his chin. "I have faith."

"Really? In your unborn baby-God?"

"Yes," the angel snapped through gritted teeth. Because of course Dean couldn't, just for once, _once_ in his life, believe in Castiel or follow _him_ for a change.

As though determined to prove him right, Dean shook his head. "Well then you're a dumbass."

Castiel shook his head without arguing; there was nothing he could say to make a Winchester change his mind, anyway. Instead, he demanded, "Have you seen enough?"

The boys took one more slow circle, both swallowing hard and obviously straining to keep their expressions blank. Castiel understood, and was relieved when Sam met his eyes again and replied with an uneasy nod. Together, they turned back to the rift, and once again Castiel led the way through.

The sudden shift from stormy daytime to heavy night left him briefly disoriented, but Castiel's priority was his human friends and he immediately turned to face them.

"Are you alright?"

"No, Cas," Dean snapped back. "Pretty far from alright. I mean, we've got Lucifer on this side, we've got Mad Max world on that side. I mean, yeah, we've been down before, but _this_? I- I mean, I don't even know where to start."

The hunter turned, then jolted slightly at the figure standing there behind them.

"Oh, come on!" Dean yelled as they registered it was only Crowley.

"Hello, boys. Again."

"Wait a second," Sam snapped. "How the hell did you-"

"I improvised," Crowley interrupted as he held up a bandaged hand that must have meant something to the Winchesters. The demon smiled. "Lucky I did. Turns out, I'm the answer to all your problems."

Castiel bristled at Crowley's pompous arrival, a thousand questions and accusations springing to mind, because of course Crowley must have had something to do with Lucifer _not_ being in the Cage like he was supposed to be. And if Crowley was here, then Lucifer probably wasn't far behind.

But before Castiel could launch into a tirade against the demon, Crowley started speaking again.

"This works out rather well, actually. I know a spell that can seal this tear in reality. And all you have to do is make sure Lucifer is on the other side when it closes."

For a moment, no one said anything. It sounded so…simple.

"Seriously?" Sam finally said.

"What do we need?" Dean asked, immediately jumping on the idea.

"I'm not sure about this…" Castiel started.

"It's not like Apocalypse World can get any worse," Dean snorted, gesturing at the rift and the barren wasteland contained beyond.

Castiel's mouth thinned. True…

"Lucifer wants the end of the world, he can have one," Dean went on, and turned back to Crowley. "What do we need for this spell?"

"Basic ingredients. I can get them all quickly," the King of Hell replied.

"Okay," Sam broke in, "but how are we supposed to keep Lucifer on the other side once we get him there?"

Castiel frowned. They all knew from personal experience that Lucifer was too strong for them.

"It's too difficult to get close enough to engage him," he pointed out.

Crowley canted his head in contemplation. "Then how about something that works from a distance? Angel killing bullets should do the trick."

"Angel killing bullets?" Dean repeated. He pursed his mouth appreciatively. "Awesome."

Castiel slid a dark, sidelong look at him. Those were bullets that could easily be used to kill _him_ , if Dean cared to notice. The hunter's smile faltered, and he gave a half shrug abashedly.

Crowley smirked in amusement. "I'll get everything we need. Be back in a jiff." In the next eye blink, he was gone.

"Okay," Dean said, sounding slightly disbelieving. "We actually have a shot at getting rid of Lucifer."

Sam's throat bobbed with obvious trepidation. "So we lure Lucifer through the rift, Crowley does the spell, and we all get back through before it closes." He and Dean exchanged a look.

"Right," Dean said. "So, long shot as usual."

Castiel shifted his weight anxiously. He still wasn't sure about this. But if he was going to have any chance at keeping Jack safe, they needed to get rid of Lucifer once and for all.

Crowley reappeared with a knapsack in hand. He opened the flap and pulled out a good size box, which he tossed to Dean. The contents rattled as the hunter caught it. "That should be enough," Crowley remarked.

Dean opened the lid, eyes widening at the hundreds of silver bullets inside. "Where did you get all these?"

"Melted down angel blades, of course."

Dean shook his head, once again looking impressed. "I've got one of the British Men of Letters' submachine guns in the trunk."

He headed off that way while Crowley eyed the glowing rift. "Guess I'll go get set up, then."

Castiel hesitated a split second before deciding, "I'll go with you. That place can be disorienting on your first visit." He caught Sam flashing him a tense look, and then turned to escort Crowley into the alternate reality.

Travel through the rift wasn't getting any easier, and it still left Castiel briefly nauseated when he stumbled out the other side.

Crowley raised his brows in bewilderment as he took in the environment. "Ah, yes, I can't think of a more fitting place for Lucifer."

"How about the Cage?" Castiel snipped. He still didn't know how that had gotten colossally screwed up, and if it weren't for Crowley having a solution now, Castiel might very well have been tempted to stab the demon through the throat.

Crowley heaved a dramatic sigh. "Yes, well, we've all made mistakes, haven't we, Castiel?"

He gritted his teeth and turned away, casting a wary gaze around the area. "We have to hurry," he said tersely. "The longer the rift is open, the greater chance it will draw attention."

There was a rustle of wingbeats, and Castiel stiffened as his prediction was just confirmed. But the angel that landed before them was simply his counterpart.

"What are you doing here again?" the other Castiel demanded, skewering them with a glacial glare.

Crowley's eyebrows shot up to his receding hairline. "My, my, Castiel. I must say this isn't how I pictured you."

Castiel rolled his eyes to the broiling sky. He really didn't have time for all this, not with Lucifer on their tail and Kelly about to give birth.

His counterpart narrowed his gaze on Crowley. "You're working with a demon?" he asked, a harsh edge in his tone, much like when he'd learned about the nephilim.

"This is Crowley," Castiel reluctantly introduced. "He's here to close the rift."

"What happened to your nephilim fixing it?" his alternate replied sardonically.

Castiel clenched his jaw; he was getting tired of having to defend his actions to everyone. And somehow having to do it to…himself, was even more of an affront.

"There's no time. Lucifer is on his way. The nephilim is his offspring, so I'm sure you can understand why we can't let him take the child."

His counterpart stared at him in stupefaction yet again. After a long moment, he finally spoke in a low tone, "You're planning to trap Lucifer here."

Castiel's spine snapped taut, and he tried to think how he might craft a believable misdirect.

His alternate shot him a wry look. "It's what I might try."

Castiel swallowed hard. "I'm sorry, I'm not trying to condemn your world. It's just…"

"It's already condemned," his counterpart finished bitterly. He fell silent, and Castiel wondered whether he would try to stop them. Could Castiel fight…himself? But they were running out of time.

"Not to interrupt this fascinating exhibition of narcissism," Crowley put in, "but tick, tock, Castiel."

Castiel tensely watched his counterpart shoot a dark look at Crowley. But then after another beat, the other angel lifted his chin.

"I will help you."

Castiel blinked. "You will?"

"As you said, this world can't get any worse." His jaw worked for a moment before his mouth quirked a fraction. "We both have a penchant for crazy plans," he said. "Perhaps bringing Lucifer here can help us, give us a do-over at the final fight and a chance to end this war."

Castiel frowned. "What do you mean? Where's Lucifer in this reality?"

"Dead. As is Michael. They destroyed each other, and thus there was no victor in the fight to decide the fate of the world."

"Then how…?"

"You let me worry about that." He canted his head in thought once more. "After you lure Lucifer here, I can help keep him occupied. If I change my appearance to match yours, it will confuse him when we strike together."

Castiel was taken aback by the readily offered help. But, as his alternate had said, they were apparently still alike in some ways.

"Alright," Castiel said. "Sam and Dean- um, my friends, will also be working with us. Dean will attempt to use angel killing bullets on Lucifer when he first comes through." Castiel would be naive to believe those would actually _kill_ the Devil, but they only needed to distract him long enough for Crowley to complete his spell.

Castiel's counterpart lifted his brows a fraction. "I wasn't sure you had those in your reality, since I don't see you carrying a gun."

Castiel paused. "You mean angel killing bullets? Are they…common here?"

His counterpart shrugged, and drew his semiautomatic pistol from its holster. "Bullets for angels, demons, and everything in between."

Castiel…wasn't sure how he felt about that.

Crowley arched an eyebrow. "And who, might I ask, is credited for that invention in this reality?"

Castiel's alternate gave the demon a blank look. "No one. When war became a constant state of existence, both sides adapted. Guns are a lot easier to use than blades."

Castiel frowned at that tidbit. He'd used projectile weapons on and off before, including the Colt rather recently, but he couldn't imagine himself trading his blade for such conventions permanently.

"Well," Crowley huffed. "Shall we stop lollygagging and get to work?"

"Of course," the alternate said, sounding for the first time almost exactly like Castiel. It really was rather disconcerting to be interacting with another version of himself.

Castiel watched his counterpart look down at himself, and in the next moment, his military uniform had been replaced with an exact replica of the clothes Castiel was wearing, even the tie. He had to admit he found the mirror image even more jarring than the commando version. But even more than that, Castiel was struck by the sudden realization that this incarnation of himself never lost his grace, or his wings. His powers were intact and effortless in a way Castiel's had not been for…a very long time. It left him with a strange pang of grief, which was confusing. There was no reason to envy this Castiel, whose world was lost to fire and brimstone. And yet…this Castiel also hadn't caused the Fall of all the angels, probably hadn't even turned against Heaven. Though, his willingness to help them here without reporting to his superiors was an odd difference.

Castiel shook off his thoughts. They didn't have time to dwell on philosophical musings.

"And…you're okay with working with a demon?" he checked.

His counterpart angled a musing look at the King of Hell. "Crowley, huh? Working to sabotage the Apocalypse?" He shrugged. "I guess that makes me Aziraphale."

Crowley raised his eyebrows. "Hm, I like this Castiel."

Castiel felt a flicker of irritation, but mostly confusion as he recognized the reference to _Good Omens_. "I don't understand. Why would Metatron have downloaded a bunch of pop culture into your brain in this world?"

His alternate rolled his eyes. "Once again, I have no idea what you're talking about. I read the book."

Castiel blinked. "Oh." That seemed…strange. When would the soldier version of him have found time to read a work of human literature?

"Well, then," Crowley spoke up again, addressing the alternate Castiel. "Let's go on where I do the good thing and you do the bad one."

Castiel was shocked when his counterpart smirked in seeming amusement. He was suddenly uncertain about leaving these two alone. Not that he had much choice.

"Alright," Castiel said. "I'll go get ready with the Winchesters."

He headed back to the portal, taking a deep breath before entering. He hoped this would work.

SPN SPN SPN

Castiel fingered the hem of these unfamiliar clothes, marking the impracticality of them. The shoes were not meant for rough and dusty terrain, and the trench coat had to impede fighting if it happened to billow under an assault of a sulfurous geyser belching from the bowels of the earth. But then, this traveling salesman version of himself didn't have to worry about such things where he came from.

Castiel couldn't fathom how he had turned into… _that_. What circumstances would lead him to defending a nephilim and working with a demon? Or with humans, for that matter? Castiel felt strangely grateful for his life all of a sudden, despite the hardships he'd had to bear.

"This way," he said to the demon, leading him around a sand dune to a place he could set up his spell out of sight.

"I must say," Crowley remarked, "you're a lot less the dogged angel of Heaven I'd been expecting."

"I'm not allied with Heaven," Castiel replied.

Crowley made a thoughtful hum. "Guess some things are inevitable in all realities."

Castiel considered that for a moment. Had his counterpart left Heaven as well? It wasn't surprising, given the news of the nephilim, which turned out to be _Lucifer's_. What was his alternate thinking? A nephilim was dangerous enough, but the spawn of the Devil himself?

"Are you also buying into the nephilim saving the world?" he abruptly asked the demon.

Crowley didn't bother looking up from the spell ingredients he was setting out. "I don't bloody care anymore," he replied blithely. He did pause then and looked up. "If Lucifer is dead in this world, who's ruling Hell?"

"The Prince of Hell, Azazel." Castiel replied.

"Hmm." Crowley shrugged. "The road not taken."

Castiel quirked a confused brow at him, but didn't bother asking what the demon meant by it. His mind was too busy with roiling thoughts and doubts about this plan. Would bringing another Lucifer over really give them a second chance at victory? At ending the war? There were still two archangels who could oppose him, but Raphael had gone insane not long after Michael's demise. He'd become a raving warmonger, but didn't even have command of Heaven's armies anymore. It was anarchy upstairs as much as below, for not all factions of demons followed Azazel.

No, the only other contender was Gabriel, but Castiel was loathe to see his brother forced into that kind of fight to the death. If Lucifer prevailed… Castiel didn't even want to think about it. Gabriel was the one thing that kept Castiel soldiering on, him and the ragtag group of angels their rogue elder brother had recruited to leave the depravity of Heaven and follow their original mission—to fight for good and protect humanity.

No, Castiel could not bear to watch Gabriel enter a fight that had destroyed two archangels the first time.

His thoughts turned to the nephilim then, and how his alternate was so convinced it could save his world. Would that kind of power be enough to turn the tide in the war here? It was a crazy idea…not that Castiel hadn't had those before. His counterpart believed he could raise the child to be good, so perhaps they could do that here. After all, if any world _needed_ saving, it was this one. The other Castiel had already averted the Apocalypse. Universal peace for a world that wasn't dying was a waste.

Castiel paced as he wrestled with the idea forming in his mind. Gabriel would probably smack him upside the head for considering it. Castiel would have consulted him, too, except he was currently on a covert mission in Egypt and under radio silence. And there wasn't time, which meant Castiel would have to make the hard choice on his own. He did not know if this was the right thing to do or not. All he knew was that he would do whatever he must to protect his family.


	3. Or Close the Wall Up With the Dead

_A/N: thanks to Loreley for your comment. There will definitely be a few familiar faces in the alternate world ;)_

 _You know we can't get through a fic without a little Cas!whump so... Yeah, here we go ;)_

* * *

 **Chapter 3 - Or Close the Wall Up With the Dead**

Castiel stepped out of Kelly's room and exchanged a look with Mary. She gave him a wordless nod and went back inside to coach Kelly through the imminent birth. Castiel regretted not being able to be there as he'd promised, but he was glad for Mary in that moment, her understanding and willingness. This should not have been the Winchesters' responsibility, yet they all had stoutly assumed their roles in this fight. As had he.

He headed downstairs to meet Sam and Dean, and then the three of them exited the front door to get ready. But they were out of time.

Lucifer stood in the yard, posture relaxed, expression smug. "Well." He exhaled an exaggerated breath. "This is a fun surprise."

Castiel dropped his blade into his hand.

"I gotta hand it to you guys," Lucifer continued. "You never give up, even when you should. Even when it would be so stupid not to."

Sam drew his shoulders back, despite the waves of anxiety Castiel could feel radiating from him. "Look, whatever you're planning on doing, Chuck- God will stop you, just like he did last time."

Lucifer hummed thoughtfully. "You're right. What should I do? Oh, God!" he cried mockingly, raising his hands and cowering. "Don't strike me dead!" His laugh reverberated harshly in the night. "Come on, Sam. You sound like a virgin in Jesus camp." Lucifer raised his voice to a high-pitched simper, "We can't. God is watching."

Castiel bristled at the irreverent tone, because _Lucifer_ was the one who'd been able to reconcile with their Father, gotten to air his grievances and come to some sort of…truce. And now the Devil was throwing tantrums again. What a surprise.

Lucifer shook his head, demeanor returning to normal. "No. Chuck walked. He's gone."

"So you're just gonna smash his toys?" Dean said.

Lucifer shrugged. "Exactly. 'Cause every time I look at this sad, trash fire of a world, you know what I keep thinking? I could do so much better."

"So Apocalypse, take two," Dean replied. "That's your plan?"

"When in doubt, go with the classics. That's what I always say."

Lucifer's eyes darkened a fraction as he stared them down. None of them blinked. Castiel, Sam, and Dean, they stood shoulder to shoulder as a united front. Team Free Will, as Dean had called them.

"Well, boys," Lucifer spoke again. "Enough with the foreplay. Let's do this."

Castiel tightened his grip on the hilt of his blade.

"See you on the other side, boys," Dean said quietly.

Castiel surged forward. It was a futile gesture, more for show than anything to give the Winchesters a reason to run. He expected the invisible force that slammed into him when Lucifer flicked his wrist, and Castiel was flung through the air several feet. He landed harder than intended, though, the impact jarring his spine and skull.

He must have been knocked out momentarily, because when he blinked the dark haze from his head and looked up, there was no sign of Lucifer or the Winchesters.

Panic flared through him, and Castiel pushed himself to his feet, stumbling around the house to the backyard. The rift crackled and oozed orange plasma, yet as Castiel strode toward it, there was a small 'brrp', and the edges shrunk a fraction. Crowley must have completed the spell, and Sam and Dean must still be on the other side.

Castiel tried to brace for whatever he might find as he launched himself through the portal. He had a split second of relief as he nearly collided with the Winchesters standing right near the rift, ready to exit, but Lucifer was several yards away, and Crowley's body was crumpled on the ground at the Devil's feet. Castiel felt a thrill of fear that he hadn't been able to complete the spell.

There was no sign of Castiel's double; maybe he was attempting to finish the casting himself.

Lucifer started toward them, but Castiel knew they couldn't let the Devil get close enough to returning to their world, and so he pushed past Sam and Dean to intercept Lucifer and buy them time.

Dean shouted for him, but Castiel didn't waver. He was determined to finish this once and for all. Plus he still had the ace up his sleeve with his alternate.

Dean's cries cut off with the whoosh of the rift, and Castiel allowed himself a modicum of relief that at least he and Sam were safely back now.

Castiel swiped his blade, but Lucifer caught his arm easily. Castiel merely swung a punch with his left fist, smashing it against Lucifer's cheek. The Devil's nostrils flared with rage, and he cranked Castiel's sword arm back until it gave a resounding crack. Castiel grunted as he briefly lost feeling in his fingers, but it was enough for Lucifer to snatch the blade out of his hand.

Castiel tried to wrench away, but failed to avoid the pommel being slammed into his temple. Stars burst across his vision and he staggered, but remained upright with Lucifer still holding his fractured arm.

The Devil leaned in close and sneered. "When will you learn, Castiel? You can't defeat me. I know every single one of your weaknesses." He dropped his voice to a husky breath, "Intimately."

Castiel head-butted him. He felt the crunch of cartilage, but knew the archangel would heal just as instantly.

Lucifer's eyes flashed red, but then flicked distractedly to the side. Castiel reflexively followed his gaze, and spotted his mirror self. _Yes_. They could still do this.

Except instead of coming to his aid, the other Castiel was striding straight toward the rift.

Castiel's eyes widened in alarm. What was he doing? That wasn't the plan!

Lucifer whipped back to him with a snarl. "You little…" He thrust the angel blade into Castiel's stomach.

Castiel couldn't hold back a cry as the celestial alloy was ripped back out with a tearing and burst of raw grace. Lucifer tossed him aside, and Castiel's legs gave out before he could catch himself. Rather than finish him off, though, Lucifer spread his wings and flew to the portal.

Castiel clutched at his stomach and tried to roll into an upright position. He didn't know what the Devil thought had just happened, if Castiel had tricked him with an illusion worthy of Gabriel's cunning. Either way, Lucifer had escaped _back_ into their reality, ruining everything.

Castiel pushed himself up on one knee and tried to take a step toward the rift, but he fell forward onto his hands. Hot blood pulsed from his wound and his vision was spotting.

 _No_. He had to save Sam and Dean, had to save Jack.

Castiel gritted his teeth and began to crawl. He was too far away, though, and the rift made another spritzing sound as it shrank another degree. Had the spell to seal it been completed after all?

Another explosion of pain tore through his abdomen, and Castiel nearly collapsed face first in the sand. He closed his eyes in dismay. He'd failed. _Again_. And colossally. Again.

The rift made another whooshing sound, and Castiel managed to lift his head. For an instant, he almost wept with relief as Lucifer came falling back into this reality. But then… _no_. Mary tumbled in after him. She scrambled to her feet and spun around, just as the rift finally sealed completely and vanished.

SPN SPN SPN

Mary stared at where the rift had been only seconds before, now out of her reach forever. Her reach, but Lucifer's as well. His raging bellow echoed against the rumble of distant thunder. Though it had been her plan to sacrifice herself for her boys—for her _world_ —if necessary, the horrifying reality of what that meant settled over her in a paralyzing wave.

Not that it mattered, she thought with hard bleakness. She doubted she'd have to suffer this world for long; Lucifer would see to that.

Shifting her gaze to the Devil, Mary swallowed back the lump in her throat as his thunderous glare rotated in her direction, zeroing in. A red light flared in his eyes, filled with cold fury that pierced all the way down to her soul. So this was how it ended.

Well… there were worse ways to go. Her sons were safe. Her world, all of it was safe.

"You…" Lucifer hissed, bearing down on her. "Little… _maggot_."

Mary's fists clenched on the warded brass knuckles, taking a slow step back for each that the archangel took towards her. There was nowhere to run, not when he had wings.

Lucifer thrust a hand out towards her. His power lashed out in a forceful wave that flung Mary from her feet. She struck one of the monoliths, head cracking against the hard surface, and then crumpled to the ground, stunned.

The Devil's teeth were bared as he stormed her direction. Though Mary forced her arm to raise in defense through her daze, she was already internally bracing for the inevitable.

It never came.

Mary's eyes widened in shock as another form crashed into Lucifer, knocking him away from her in a rush of tan. But… that was impossible. How hard had she hit her head? Mary stared, frozen, as Castiel—the same angel that she had just seen murdered by Lucifer—now fought to keep the Devil away from her.

"Oh, come _on_!" Lucifer bellowed as both angels rolled to their feet and separated, Cas standing between Mary and the archangel. Lucifer's eyes flashed red again, glowing like hellish embers in the gloom. "How many times do I have to kill you for you to _stay dead_?"

Cas staggered, but stayed on his feet. Mary could only stare at his back, where there should have been a lethal puncture wound all the way through. She had seen it with her own eyes, not thirty seconds before, in their own world. Now, through the fog of hitting her head, Mary could see the blurry outline of his coat—and while it did seem to be slowly soaking through with blood, it was in the wrong place, too low for the chest.

"At least once more," Cas gritted out.

Lucifer bared his teeth as a blade dropped into his hand. He pointed it at Castiel and seethed, "Gladly."

Mary heard the mighty _whoosh_ of unseen wings as Lucifer disappeared only for a second, flying forward directly at Cas. The Devil reappeared with a vicious slash of his blade. Cas cried out as the attack caught him across the chest; the glow of grace from the wound briefly illuminated Lucifer's ferocious, nearly insane wrath. The angel stumbled back, but Lucifer pressed his advantage. He took another swing, this time snapping Castiel's face to the side and scoring another shining line of blood.

Cas tripped backwards. When Lucifer's arm swung again, the angel could no longer keep his footing, and was thrown to the ground. As Mary's head cleared, she stared in horror at the visible wound in his gut that Cas had been pressing a hand against, coating his palm in blood. She still had no idea how he could even be there, how his wounds were different now, how he was alive… but if Mary didn't act, he wouldn't be for much longer.

She had just watched him die once. Mary refused to watch it happen again.

With gritted teeth and all her determination, Mary forced herself to move, lurching to her feet. She clutched the monolith for support, her focus zeroing in on the fighting angels. Lucifer was looming over Castiel now, blade raised.

"This time," Lucifer snarled, "I'm going to make sure it sticks." He stomped down on the belly wound, eliciting another scream of pain from the downed angel, then pressed his boot onto Castiel's extended wrist, pinning him to the earth so that he couldn't roll away or get to his feet again. The Devil's feral expression darkened and he flipped his sword into an overhanded grip.

Surging forward, Mary threw herself at Lucifer, fist already flying. The brass knuckles collided with his cheek, but instead of knocking him back as they had done before, Mary felt her hand nearly break. She cried out at the unexpected pain and clutched her wrist. The sigils etched into the brass knuckles remained dull and lifeless; there was no power running through the weapons anymore.

Lucifer paused, gleaming eyes shifting her direction. His gaze flicked once to the brass knuckles, then back up to her face. The Devil started to smile.

Gasping, Mary threw another desperate punch that he didn't try to avoid. Though the hit was a solid one, Lucifer didn't move an inch.

 _Oh shit…_

"Doesn't seem to be working, does it?" Lucifer asked with a mocking sneer. He looked down at the angel trapped under his boot, then flipped his blade around again. "I'll get back to _you_ in a minute, Castiel. First, I think I'll gut the woman."

"No," Cas choked out, trying to shift away from him. "Mary, run!"

Run? Even if she had been willing to leave an ally behind—and Castiel was more than that to her by now—where was she supposed to go? Mary shook her head and raised her fists again. She would go down swinging if it was the last thing she did.

Lucifer snorted with laughter and stepped away from Castiel with one more harsh kick into the angel's unprotected side, advancing now on Mary instead. He raised his weapon and she once again prepared for death.

And once again, it never came.

This time, the interruption came in a rush of stampeding feet, guttural yells, and hair-raising howls. Mary's eyes widened, mouth falling open as she caught sight of the horde that had just crested the hill, barreling straight for them. Though the boys had mentioned the demons here had horns, she was still unprepared for the nightmarish image. Her breath caught in her throat, icy dread flooding through her. Mary would have preferred immediate death from Lucifer to whatever tortures she and Cas could potentially suffer at the hands of a demon army.

Lucifer's icy rage shifted to macabre delight as he turned to greet the swarm. He raised a hand, voice booming out,

"Come, my children! Daddy's here!"

But the demons didn't stop or even slow down. Mary had just enough time to see Lucifer's face wrinkle with confusion before the horde launched themselves on him in attack.

Though Mary shared his shock, she didn't hesitate. Lucifer had drawn the demons' attention, which was the only window of opportunity she was likely to be provided. Throwing herself to Castiel's side, Mary grabbed the angel's arm and started dragging him away from the fight as fast as she could. Behind them, she could hear Lucifer cursing and snarling, mixed with the sounds of bodies being flung aside. Mary doubted even a demon army would be enough to take him down, but she planned to be far away by the time they realized that.

"Come on, Castiel," she groaned, puffing with exertion as she threw her entire body weight into pulling the angel along. "We gotta move!"

"Mary, go," he gasped out in reply. "You can make it if you leave me-"

"Shut up and help me out." Mary's eyes swept the surrounding area, noting a hill directly ahead of them. Getting up the knoll would be a trial, but if they could make it to the other side, they would be out of sight of the exposed basin the rift had been situated in. "Can you stand?"

"I- maybe."

Without stopping her forward momentum, Mary heaved upwards with all her might, helping the angel clamber to his feet. Even then, she had to grab hold of him so he wouldn't topple right back over. Cas's breaths hitched out in tortured moans of pain, but with his arm wrapped around Mary's shoulders and both her arms around him, the two of them managed to limp as fast as they could up the ridge.

She didn't dare look back until they had reached the top and started down the other side. Only then did Mary chance a quick glance over her shoulder at the sound of the battle, just in time to see Lucifer throw the crowd of demons explosively away from him, clearing a wide circle. The archangel disappeared, probably flying to safety to lick his wounds. Thankfully, the maneuver left the demons disoriented enough to buy Mary and Castiel a few more seconds to descend the hill, out of sight.

The hunter hoped they didn't try to pursue her and Cas. The pair had no chance of outrunning anyone, not with her practically hauling the angel along on her own.

"We gotta get as far as we can," she gasped out, trying to urge him to move faster though the poor angel had to be at his limit. "Then we can find shelter."

"Mary-"

"Don't."

"But I'm only slowing you-"

"I said _don't_ , Castiel," she snapped with a fierce glare. "Don't talk. Save your energy. I'm going to get us out of here, if it's the last thing I do."


	4. Our Swords Will Not Be Sheathed

_A/N: Thank you Loreley and Guest for your reviews! :)_

 _Some much needed comfort and care for our Cas before the action starts up again..._

* * *

 **Chapter 4 - Our Swords Will Not Be Sheathed**

Mary and Castiel stumbled across the rough terrain, nothing but their panting breaths in the gloomy air. Mary felt Cas's tension as he tried to brace himself for every footfall. There was also a very real danger that they were leaving a blood trail, the wound in his belly dripping a crimson set of breadcrumbs for even the least observant enemy to follow. Not to mention the tracks left behind them in the dust. She would have to come back and cover their trail once they'd found somewhere to take refuge in for a while.

Mary wasn't sure how far they made it before it was obvious Castiel was about to collapse. They'd been half running, half limping for what must have been at least twenty minutes. She couldn't bear to hear him biting back a moan of pain any longer, or feel his body shuddering in her grip. Clearly, he was never going to admit that he could take no more, so Mary made the decision for them.

"Over there," she murmured, nodding to what must have been an old settlement long since abandoned. The skeletal remains of a few buildings still stood, lined in a row as though this had once been a populated street corner. Electing the one that still had four dilapidated walls and most of a roof, Mary urged Castiel towards it.

Slipping inside, she eased Castiel down into the corner, wincing as he hit the floor with a muffled cry. The angel immediately closed his eyes and leaned into the walls with a shudder. His hand covered the wound in his gut again, and now Mary could see the slashes across his chest and face were still welling with blood, while a purple-black bruise covered the better part of his left cheek and temple.

If only they had some water… but the hunter doubted very much the plumbing would still be working.

"Okay, you with me?" she asked softly. "Just… stay awake, alright? I'm going to double back for a ways and cover our tracks, and I'll be right back. I promise."

Castiel nodded, not opening his eyes. Mary straightened back up and hurried out the way they'd come, following the imprints of their feet in the dust for at least a quarter of a mile.

Obliterating any trace that they had come through, covering the blood trail and foot prints in hastily shifted dirt, was mindless work. Only her state of high alert and wariness for more enemies prevented Mary from disappearing into grief, but she refused to let her thoughts turn to what she had lost. More pressing was what she was supposed to do for a wounded angel, and again the mystery of how he had survived Lucifer's killing blow back in their own world and gotten through the closed rift with neither of them noticing. The more she thought about it, the less sense it made.

At least Castiel was still breathing when Mary returned to him at last, continuing to sweep her footprints away as she backed into the building once again. The angel's eyelids fluttered open, exhausted but still fierce with the doggedness she was coming to associate with him.

"Hey," she murmured, kneeling beside Castiel and settling a gentle hand on his shoulder. "How are you holding up?"

His breath hitched, but the angel winced and tried to sit up straighter. "I suppose it could be worse," he said. His forehead wrinkled as he amended, "Though I'm not sure how."

Mary saw that he was still clutching his stomach, which didn't seem to be healing. Shrugging out of her jacket, then her outer shirt, Mary tore a wide strip off the flannel.

"Here," she said. "We need to put some pressure on this."

Glancing down, Castiel reluctantly moved his hand aside, giving Mary a better look at the ghastly wound left by what must have been an angel blade. And yet, it was _not_ the same wound she had seen him receive. His chest was marred by an angry gouge of red, but it wasn't the killing blow that had ignited an explosion of supernova proportions.

"I don't understand," she said, dabbing the belly wound and trying to ignore his hiss of pain. She didn't let up, increasing the pressure a bit at a time until she could press and hold the makeshift bandage in place without the angel crying out. "I _saw_ you, Castiel. I saw Lucifer stab you on _our_ side of the portal. I saw you die."

The angel paused, looking back up at her with an unreadable expression. "He… he died?"

"He?"

"Yes, my... counterpart from this world," Castiel explained. He sighed. "So Lucifer killed him."

"You mean… you and… the _other_ Castiel, you… switched worlds? I don't understand."

With another sigh, Cas looked away. "I met him—met myself, I suppose—the first time I came through," he murmured. "He agreed to help. We were supposed to work together, confuse Lucifer and keep him distracted long enough to shut him on this side of the portal. But he—the other Castiel—I don't understand. I don't know why he broke from the plan. He was never supposed to go over to our world, he was…"

The angel trailed off, closing his eyes and slumping down with a shudder. He shook his head.

"And now Lucifer's killed him." Castiel's shoulders tensed, eyes snapping back open again as he caught Mary's gaze with a flash of panic. "Wait… what about Sam and Dean?"

"They're fine," she assured him, touched by the devotion this angel clearly still had for her boys. Though Mary tried to keep her emotions in check, she was mentally and physically exhausted, and it was difficult to keep her eyes from welling with tears.

They were fine, and that was what mattered, but… but she had just gotten them back again. After the nightmare of having her mind pulled apart and remade into a puppet, Mary had only just started letting herself believe that things would still turn out alright.

She should have known better.

Dean was right, everything that had happened was her fault, from the moment she had made that deal with Azazel. Because of that one decision, her boys had grown up without a mother, almost without a father, constantly hunted from all sides. Even if Dean and Sam had forgiven her, it didn't change how much strife she had brought down on them, her _children._

And not a full week after finally coming together again as a family, they had been ripped away from her.

Again.

While she struggled to control herself, the angel still crumpled on the floor released a slow exhale and nodded.

"They're okay," he murmured. "And Lucifer's here, forever. Then nothing else matters."

Castiel shifted, then immediately hissed with a choked whimper of pain.

The sound brought clarity back to Mary's mind; two of her boys were safe from Lucifer, but one was still grievously wounded, and they couldn't afford for her to wallow in misery.

"Here," Mary said, giving herself a shake. "Let's use your tie to keep this in place, and I can start looking at these other wounds."

"There's really no point-"

"I promise you, I'm more stubborn than you are," Mary cut in over him, angling a severe look at her patient. "So you might as well let me take care of you."

Castiel's lips twitched. "Well, you are certainly your children's mother," he murmured.

Mary smiled. There were a few tattered blankets flung in the opposite corner, probably from where some other poor human had also once taken shelter here. She grabbed those and brought them back to spread out on the floor, then helped Cas shift so he could lie on top of them. Finally, she bundled her jacket up behind his head for a pillow. He flashed her a grateful look underneath the weariness making him slump further.

The wound in his gut reminded her horribly of Ramiel, of Cas splayed out on the couch as his life slowly ebbed away, but at least this time the injury didn't seem to be poisoned.

Still, the reminder was too stark, the horror too near, and Mary had to take a deep breath to stop her hands from shaking. A flash of red illuminated the dubious shelter, drawing her attention to the darkening sky outside. The storm had yet to lessen; it was probably as permanent a fixture in this world as the war that raged without end.

She had no water to clean his wounds, no food to keep either of their strengths up, a useless set of brass knuckles and the angel blade she still had tucked away as their only weapons… no allies, no idea where to go, and no way of ever returning home. With hordes of demons who would probably kill them on sight - if they were lucky.

Castiel was right: perhaps their predicament could still somehow get worse, but she had no idea how.

SPN SPN SPN

Castiel shifted in discomfort on the pile of ratty blankets cushioned beneath him. He'd grown more anxious as darkness had fallen, pitch-black shadows seeping into every corner of their rickety shelter. The fact that it was broken with a constant barrage of red flashes suffusing the air outside and through the broken slats of the windows and walls only made the night more terrifying.

Wind howled eerily, and loose planks of wood banged against the building. Castiel worried about demons finding them, as the denizens of this world were more frightful and monstrous than the ones he was used to back home. No, these manifestations were closer to what one would find deep in the Pit, demonic essences in their true forms. Castiel barely had the strength to take on a pure demon fresh from the bowels of Hell; how was he supposed to protect Mary from them here?

An eruption of crimson lightning illuminated her profile where she stood next to a window, nervously scanning the area. At least Lucifer wasn't likely to find them. Castiel didn't know where the archangel might have fled to, but he was no longer their concern anymore. Survival was.

Mary shivered, and stepped away from the window. Even Castiel felt a chill creeping across his skin, whether due to blood loss or the toxic atmosphere of this place.

"I'm sorry you're here," he spoke up quietly, voice barely loud enough under the echo of thunder.

Mary turned toward him. "What?"

"You were never supposed to be put in danger," Castiel explained morosely. "If I hadn't let Lucifer make it back through the rift…"

She came to stand over him, flicking a pointed look at his bandaged abdomen. "There wasn't any _letting_ involved," she said, crouching down and sitting cross legged on the floor at his side. Something haunted wavered in her eyes. "God, Cas, I thought you'd _died_. When Lucifer…" She gave herself a small shake. "It was like losing one of my boys."

Castiel could only gaze at her owlishly. He'd considered her part of his adoptive family the moment she had come back into Sam and Dean's lives. Then they had worked together, shared late night conversations about dislocation and belonging, and he had come to know and respect her, as a hunter, as a woman just trying to find her way. It had never once occurred to him that she would see him as anything other than an ally of her sons. Even in Ramiel's barn, it was Sam and Dean who had staunchly refused to leave him. And of course Mary wouldn't leave without _them_...

She reached out to take his hand in both of hers. Caring, protective, like Castiel had done for Kelly.

Mary gave him a wan yet genuine half smile. "One thing I'm grateful for in all this, is that you're not trapped here alone."

Hot tears pricked at the corners of his eyes, and he sucked in a shuddering breath because deep down he was grateful for that too, even though it was selfish, even though he should never wish for someone else to be stuck in this hellish nightmare forever. And it wasn't that he _wished_ for that, but having Mary here...it gave Castiel a reason to keep fighting. Something he probably wouldn't have had, otherwise...

Mary's thumb rubbed circles over the back of his hand. "Dean and Sam will be looking for a way to bring us back."

Castiel knew that was true. Or…rather, they'd be looking for a way to bring _Mary_ back. Because as far as Sam and Dean knew, Castiel was dead. And if Mary had watched 'him' die, then they must have as well.

He closed his eyes against a swell of grief. What they must be going through. It was Castiel's greatest fear, to watch the ones he loved die. He hadn't meant to put them through that. And add to it the grief of losing their mother… No, Castiel had to protect Mary at all costs, ensure that she somehow found her way home to her sons. And, Castiel wanted to find his way home too. Here in this desolate wasteland, he had never missed his family more. He even started to wonder why he had been so adamant about keeping Kelly sequestered, about needing to take care of her - and Jack - by himself. That drive seemed a distant echo now, drowned out by the void in his heart at being so brutally separated from his loved ones.

A battering gale suddenly struck the building, and Castiel's heart leaped with the panicked thought that demons were descending upon them. Mary jumped to her feet, but when the doors blasted inward with a resounding bang, only a single figure shrouded in night stormed inside. Gusts of wind whipped around him and howled at his heels. Castiel recognized the same uniform his counterpart had been wearing when they'd first met, and then his stuttering brain gaped in bewilderment as he took in the phantom visage he had last seen in Metatron's crafted illusion.

Gabriel's eyes narrowed fiercely on them, flicking a dismissive glance at Mary before skewering Castiel, but after a moment they widened in shock. "You're not from this world," he blurted.

"N-no." Castiel pushed himself up straighter, biting back a wince.

"How did you get here?"

Castiel flinched under the harsh tone, so unlike the jovial and glib Gabriel he used to know. War changed everyone, it seemed.

"There was a tear in reality," he started to explain. "Caused by a…" He belatedly decided it was probably best not to mention the nephilim. "Lucifer was preparing to destroy our world. We decided to attempt trapping him here, in this reality, and sealing the rift. Your Castiel thought, since the Lucifer here died, that it might give you another chance at winning the war."

So why had his counterpart aborted the plan at the last minute? What had he hoped to accomplish by going through the portal? An escape from this world? Castiel couldn't imagine any version of himself abandoning his friends for his own survival.

Gabriel was a fearsome storm of crackling fury towering over them. Even with his vessel's short stature, his presence alone dwarfed Mary as shadows went skittering away into the corners of the room.

"Then where is he now?" the archangel demanded. "The energy spike I felt, which I assume is this tear in space, is gone, and the only grace signature I can sense of Castiel is… _yours_."

Castiel tensed. Why was Gabriel looking for his alternate, anyway? And what would this seemingly mercurial archangel do with him in that Castiel's stead?

"Cas," Mary said quietly. "You know him?"

Castiel didn't know how to answer that, because he did know Gabriel, just maybe not...this one. But he nodded anyway. "Yes."

"You too, huh?" Gabriel said tetchily, giving her a casual once-over. "Welcome to the party, then. Now answer my question."

Mary rolled her shoulder nervously. "Lucifer- he killed the other Cas."

Gabriel's spine snapped taut like a whip crack. "Excuse me?"

To her credit, Mary didn't balk. "Your Castiel…ended up on our side of the portal. That's where Lucifer…" She swallowed hard. "Killed him. I watched it happen. Thought it was…" Mary cast a look down at Castiel, expression once again grief-stricken with memory. She looked back to Gabriel. "Lucifer and I ended up on this side, along with Cas, right before the rift closed."

Gabriel stared at her for a long moment as though searching for a lie. Castiel saw the moment he found the truth, because the glacial exterior cracked, and a grief as deep and profound as the one Mary had borne swept across his face. Castiel was struck then by the odd realization that the Castiel and Gabriel of this world must have been close. Had either never grown apart when Gabriel faked his death and left Heaven, or had somehow reunited in a better way than the pocket dimension in which the Gabriel that Castiel knew had tormented him and the Winchesters.

Castiel tried to prop himself up further against the wall, biting his lip against an eruption of fiery pain in his wounds. "Gabriel, will you help us?"

The archangel jolted, eyes instantly hardening again as they snapped to Castiel with renewed suspicion, and perhaps a little ire. Castiel instinctively faltered under the weight of that immense power, but he forced himself to remain still, eyes raised and openly pleading. He and Mary had nowhere else to go, no way to navigate this world without help.

A muscle in Gabriel's jaw ticked, and then he strode forward without a word. He reached one hand to Mary's forehead, the other to grab Castiel's shoulder, and then they were whisked away through the ether. Traveling by angel air was instantaneous, and Castiel blinked in the next moment to find they were in a different location, this one with four concrete walls sans cracks or decay. Castiel was now sitting on a long, black leather couch, with Mary standing at the side.

"Where are we?" he asked, looking around. There were no windows, and only one door that looked out into another room. This one was sparse, with two bookcases along the rear wall containing rows and rows of paperbacks. A Turkish rug covered the cement floor, while a small fountain burbled in one corner.

"A safe-house," Gabriel replied. "Hidden from demons and angels."

Castiel furrowed his brow. "Why angels?"

"I don't have time for a history lesson," Gabriel said tersely as he turned toward the door. "So just sit tight while I go try to figure out how much damage your little jaunt into this universe has caused."

"Are we prisoners?" Mary called after him, tone rising with a hint of dismay and indignation.

Castiel almost felt the urge to assure her that Gabriel wasn't like that…but he didn't know this version of his brother, who seemed more like a stolid soldier and less the carefree and flippant Trickster of their world. Whom Mary had also never met before.

Gabriel stopped on the threshold and threw a bland look over his shoulder. "Lady, does this look like a world where we bother keeping prisoners?" He spun around and stormed out, leaving the two of them alone.

Castiel's throat tightened as he suddenly wondered whether their situation had improved that much at all.


	5. Our Tears Will Not Be Shed

_A/N: Thank you Loreley for your review! There's more Cas and Mary interaction here, and a hefty dose of Gabriel! ^_^ Even if he isn't our Gabriel. Plus, we'll catch up on what the always creep-tastic Lucifer is up to..._

 _And thanks to everyone who's been reading so far! Enjoy!_

* * *

 **Chapter 5 - Our Tears Will Not Be Shed**

Gabriel flew as fast as his immense wings would carry him, racing across the heavens and the world below. There was no out-racing his grief, though, nowhere to run that his agony wouldn't follow. The archangel crashed to a halt on the top of a mountain, clinging to a slender pine tree to hold him up as Gabriel rode out the waves of crushing guilt and loss. Castiel…

Death was a regular fixture in the world, a reality that would one day claim them all—even Gabriel himself. The risk had always been harshly present, and yet all the archangel could think was that this _should not have happened_. Not to Castiel. Not to the angel that Gabriel had rescued so long ago, trying to fight off the demonic horde that had stumbled upon the younger warrior.

Castiel had been the first angel Gabriel had taken in, before their operation grew to the modest numbers they had now. And now… now he was just… gone.

Gabriel should have been there. He'd always believed that a real leader wasn't afraid to lead from the front lines, that a general's place wasn't hanging back in safety to sacrifice those beneath him. He'd taken the mission to Egypt himself because of how dangerous it was, never dreaming that in fact the true danger was right back here at home. And so he hadn't been there to protect Castiel, his brother.

What had the angel been _thinking,_ getting involved with all this? Tears of helpless fury burned in Gabriel's eyes, but went unshed as he angrily spun from the tree to look out over the bleak vista. The scarlet tongues of lightning flashed around them, but he was numb to the charged current in the air and oblivious to the booming thunder.

Why? Why had Castiel done it? Allowed _Lucifer_ in? After all these years, the dark archangel safely disposed of, and now he was back.

Only, a different Lucifer, Gabriel acknowledged with a scowl to rival a demon's. Just as that was a different Castiel that he had left in the safe house.

Disgust and revulsion crept over Gabriel as he recalled _that_ used up feather duster of an angel. Beaten and bruised and seemingly powerless, compared to the fierce, proud warrior that Gabriel knew. The kind of angel who would elect to dump his problems on someone else's world, as though this realm wasn't already dying. And now _he_ was here, while Gabriel didn't even have a body to bury.

The dark thought flashed through his mind that he could always kill this Castiel and bury _him_ by proxy, damn it, but of course he wouldn't. What would be the point of senseless murder? His Castiel would remain just as dead.

Slowly, Gabriel sank to his knees, head bowed as he raked shaking fingers through his vessel's hair. _Why_ had his Castiel agreed to such a stupid plan? Could the strangers be lying? Maybe Castiel had tried to stop them, and they'd killed him themselves… But as much as he wanted to blame this all on the woman and the other Castiel, the archangel knew deep down that they weren't trying to deceive him.

Plus, now that he thought about it, this wasn't even the first time Castiel had come up with such a crazy, Hail Mary ploy. There was the occasion he'd suggested they use time travel, to go back and change the past, to prevent this war from happening in the first place.

It had been a long shot from the start, but with nothing else to lose, Gabriel had agreed.

And they had failed. And it had turned out they _did_ have something to lose, a good soldier who'd been killed in the attempt. It had taken Castiel a long time to deal with his guilt over that, even though Gabriel had been the one to approve the mission.

But bringing Lucifer here… had Castiel seen it as another high-stakes, eleventh hour plan? After all, this war had started because Lucifer and Michael's fight had backfired. Restoring Lucifer could have been some kind of a do-over, another shot at the prize fight that had gone wrong.

Yeah, Gabriel could see Castiel believing that; the angel was just crazy enough to think it might work. And after what happened before, of course he wouldn't be willing to risk anyone but himself. That was the only thing that made sense—well, it still didn't make sense—because this was Lucifer and there was no way any plan involving that maniac was ever going to save them.

And yet, not even this war, this endless fight for survival, had ever managed to beat that idealistic hope out of Castiel. Damn him. How it had always exasperated Gabriel.

How it had always kept his own hope alive.

If nothing else, Gabriel thought as his hands fell into his lap in defeat, it seemed that this Castiel shared that in common. After all, what kind of harebrained scheme was it, flinging himself into an alternate reality in order to save his own world? Weak and puny though he might be, it seemed the other Castiel did at least have the same heart, the same hope.

Look where it had gotten him… trapped in a dying world. For better or worse, the other Castiel was stuck here now.

Gabriel leaned back on his heels and looked skyward, heaving a sigh. Castiel wasn't the only one stuck here… and while the ragged angel and one human might not be a threat, _Lucifer_ was.

Shaking his head, Gabriel raised a hand to touch his temple.

" _Anna,"_ he called through his own private line to his people.

" _Gabriel? I'm here. What's happening?"_

" _Oh, you know, chaos and mayhem,"_ he grumbled.

Quickly, the archangel filled her in on everything he knew, allowing his sister a moment of silent grief at the news of Castiel's death.

" _I suppose it's too much to hope that Lucifer is a code word for something that is NOT actually… Lucifer?"_ she finally asked, soldiering bravely on as Gabriel knew she would.

He snorted. " _I wish. We need to keep an eye on him. Take some soldiers, no more than two or three, scout it out. He shouldn't be too hard to find. But listen: do NOT engage, you understand me? He doesn't see you, he doesn't hear you, he doesn't ever know you're there. That's a direct order."_

" _Yes, Gabriel. What are you going to do?"_

Gabriel's jaw tightened, pondering the question. " _I'll have to get back to you on that."_

Taking wing, Gabriel flew back to a run-down, nondescript shop on the edge of a town abandoned years before. There was nothing to suggest it contained more than it seemed, nothing to draw attention—from demons, angels, or humans. The archangel stopped at the door and checked over his shoulder to be sure he wasn't being followed.

Not that it mattered. Creating pocket dimensions was child's play for him by now, and no one but his own troops were granted passage through the barrier of reality into the stronghold Gabriel had built for them.

The archangel slipped inside and strode straight for the side room where he had left the human and the other Castiel. Hearing a muffled exclamation, he drew to a halt and paused on the other side of the wall, listening.

"Sorry… sorry," the human was murmuring. "Almost done." There was a short pause before she asked, "Will your grace be able to heal these?"

"Eventually, though it might take weeks. Maybe longer," Castiel replied with obvious tension. "It's only luck that Lucifer didn't strike anything vital."

"Thank goodness."

"You need to tend to yourself, as well. You took a bad hit when he threw you into the pillar."

"No, I'll be fine. You're still bleeding, Castiel. Hold still, he got your face pretty good and I need to wash the dirt out."

Gabriel frowned, shifting around the doorway far enough to see the woman dipping a flannel rag into the fountain and using it to wipe blood and grime from Castiel's cheek. There was already a makeshift bandage around his stomach, another covering his chest. It looked like the flannel had been a shirt, obviously belonging to the woman.

The image was odd, and unexpected. A human, tending to an angel's wounds—not with the hopes of keeping him alive long enough to extract information, but with gentleness and genuine care.

Gabriel had never seen that sort of dynamic between a human and an angel before. Though he and his soldiers did what they could to protect humans, it wasn't like the effort was returned with respect or even tolerance. Humans didn't look kindly on them, because they were angels and that was that.

So to see a woman who could bear to even touch an angel without disgust, much less tend to him with something like devotion… well, this was different. Gabriel hadn't paid her much thought one way or another before, but he regarded her now with more interest.

Castiel was still lying on the couch, face tight with pain, but his eyes flicked to Gabriel as the archangel stepped through the doorway. Gabriel saw the flash of uncertainty, mixed with hope. The archangel crossed his arms as the woman spun and set a cautious hand on Castiel's shoulder. Did she think she would protect him? That was even more unusual. Not to mention pointless.

"What's your name?" Gabriel asked, addressing the woman directly.

She straightened. "Mary."

"Hmm."

Castiel was right, it did look like she'd taken a hard knock. Gabriel could sense the swelling of a concussion inside her skull. Reaching forward, rolling his eyes with impatience when she flinched, the archangel touched her forehead. The healing was abrupt and left her with a look of surprise, but Gabriel was already turning for Castiel.

The angel didn't pull away, watching Gabriel's hand as it came to rest on his bandaged stomach. The physical connection allowed the archangel to then connect to Castiel's grace, and what he saw made Gabriel feel suddenly sick. It wasn't just the wounds...

...this Castiel was a mess.

His wings were mangled, broken and useless. In all his days, though Gabriel had witnessed barbaric carnage on the battlefields and seen angels killed in the most brutal of ways, he had never once seen any with wings like this. This Castiel's grace—what little there was—was scarred and flickering. It was barely enough to even call him an angel at all. No wonder he seemed so weak, so powerless.

Even though Gabriel knew this wasn't _his_ Castiel, it still shook him all the way to his core to see the image of his brother in this condition.

Not to mention the actual wounds themselves. It had been a while since Gabriel had seen cuts from a blade instead of bullet wounds, but Castiel was right: at least Lucifer hadn't hit anything vital.

Wait a second…

"You're a wreck," Gabriel snapped as he started to infuse his healing power into Castiel's battered frame. "You can't fly on those wings. They're busted up beyond even _my_ ability to fix. You've got less power in your grace than a fledgling, and what there is looks like absolute garbage."

Castiel looked away, a flicker of shame in his features as the human, Mary, bristled. Gabriel, however, shook his head and demanded,

"So what the hell were you doing?"

"I- what do you mean?"

"What were you thinking, taking on Lucifer? In _this_ condition? Most angels at their strongest know better than to try that, and this is hardly you at your strongest."

"He was going to destroy my world," Castiel snapped back, pushing Gabriel's hand away as the archangel finished healing him. The skin glowed and melded back together, the blood and muck disappeared. Their connection broken and the horrible proof of Castiel's ruined state disappeared from view but not from memory.

"There was no way you were ever going to beat him," Gabriel said. "So, like I said… what the hell were you doing?"

Castiel shook his head. "What were my options?" he ground out with a glare. "Sit back, do nothing? I had people to protect. No, I was never going to win the fight, but I _could_ hold him off long enough to save them. And that's what I did." His steely scowl flicked to Mary and softened as he added with obvious guilt, "Mostly."

Gabriel took a step back, arms crossed. "Huh."

His own Castiel had never been so damaged; it looked like this one had been torn apart several times, by things that knew how to destroy an angel. That alone was enough to bring out the protectiveness in the archangel, and he wondered what exactly had happened to this guy.

"What?" Castiel grumbled.

Gabriel shrugged. "You're more like him than I thought."

And damn it, that hurt. Still, even if this Castiel wasn't from this world, in many ways he was still a brother. The archangel heaved a sigh, posture relaxing as Castiel swung his feet off the couch and sat upright.

"Thank you for healing me. And Mary."

"Yeah, whatever. Anyway," Gabriel said, "there's no trace of that energy spike from the rift anywhere, and I have no idea how to hop realities. Dimensions is one thing, but I don't have the juice to send you back home. Sorry, kids, looks like you're stuck here."

"Maybe not," Castiel murmured, frowning in contemplation. "This isn't the first time alternate worlds have been crossed. Back in our world, we once opened a portal- well, I say 'we', but the angel Balthazar was the one who figured out the proper sigil to use."

Gabriel snorted. "Trust me, Balthazar doesn't know how to do anything like that. And what's a… sigil?"

The angel's head whipped up, eyes wide with shock. For a second, he didn't speak, and Gabriel wasn't sure what had thrown him until he whispered,

"Balthazar… Balthazar is alive?"

"Of course he is…" Gabriel paused. _Oh_. "But I'm guessing by the look on your face, he's not, back in your world."

Still looking stunned, Castiel slowly shook his head. He swallowed, then added, "Neither are you."

"Huh. Gotta say, your world doesn't sound much better than this one."

"Maybe not for angels."

The unspoken significance of his remark hung in the air between them: the humans still had it alright, and the humans were what mattered. Gabriel eyed Castiel, again wondering what exactly he'd been through that had made him such a mess… and yet somehow not quite as broken as the archangel had initially thought.

Mary broke her silence at last, arms crossed as she asked, "To clarify… did you just ask what a sigil was?"

Gabriel glanced her way and shrugged. "Yeah, not sure what you're talking about. We're a little short on manpower, but if you tell me what a sigil looks like, I can have my soldiers keep an eye out for one."

"Well, it's a-" Castiel started, before cutting off and staring at Gabriel. "You really don't know? But… that makes no sense."

"There's a lot of that going around today," Gabriel muttered, eyes again finding Mary when she moved to pull something from her coat. He raised his eyebrows as he noted the pair of brass knuckles she now held. Those would be about as useful as a toy gun.

"These markings," she explained, holding the weapons out for Gabriel to inspect. "Those sigils are supposed to make them work against angels. It's how I managed to get Lucifer back through the portal to begin with. But then they just- I don't know, they stopped working."

The archangel examined the brass knuckles, frowning at the funny scratches etched into the surface. How was _that_ supposed to do anything to a celestial being? There was no power signature; she'd gone after _the Devil_ with nothing but a chunk of metal?

Was everyone from the other world so reckless, or just these two?

"Can't help you," he finally said. "I've never seen anything like this before."

Mary and Castiel traded a look filled with dismay.

"That's why it didn't hurt Lucifer once we were on this side," Castiel murmured. "It sounds like sigils don't exist here."

"Is that possible?" Mary asked.

"Theoretically, anything is possible," Castiel pointed out, looking at the brass knuckles again. "In the world Balthazar sent Sam and Dean to, there was nothing supernatural at all. The angel who pursued them had no power while he was there."

"So, no sigils… no portal," Mary said. Her frame crumpled slightly, eyes dimming under the weight of renewed despair. "No portal… no way of getting home."

A heaviness fell over the room, and Gabriel shifted with discomfort.

"Sorry," he said, and he meant it. "Look… I've got a small flight of angels who are still doing what we can to protect the humans. You two are welcome to join us."

As much as it hurt, looking at this Castiel who wasn't _his_ Castiel, Gabriel didn't see many other options. These two wouldn't last a day out there on their own, but they seemed to have guts and heart. Throwing that away would be stupid. Might as well make the best of it and soldier on.

It was all any of them could do.

SPN SPN SPN

Lucifer bore down on the angel squirming under his thumb. His eyes danced with delight at his captive's helplessness, mouth stretching into a predatory smirk. He needed no holy oil, no fancy sigils, nothing but his own might which it seemed angels and demons alike had forgotten.

He would remind them.

"So," Lucifer purred, raising a hand to grip the angel's chin and force his head back against the wall he was pinned to. "Your friends seemed ready enough to desert you."

"Oh, they'll pay for that," the angel spat back, not yet as frightened as he ought to be. "I don't know how the hell you got here or what world you dragged yourself out of, but you must have missed the memo… Lucifer is _dead_. Maybe things are different wherever you're from, but in this world, you're nothing but a loser who already had his shot and didn't make it!"

"Is that so?" the Devil inquired with a casual smile. His blade slid into his free hand, then came to snake along the captive angel's cheek and down his jaw. The necklace of amputated baby ears was certainly an...interesting fashion statement. One Lucifer could definitely appreciate.

He raised the blade and and circled the angel's right eye with the tip, studying him. "And what else can you tell me?"

"That _you_ will pay for this, too!"

Lucifer chuckled and shook his head. "You seem confused," he said. "See, I _am_ Lucifer, no matter which world I'm from, and I want you to tell me everything."

"Oh yeah? Well, I'm Zachariah, and I don't take orders from washed up, has-been archangels!" The angel wriggled harder, like a landed fish desperately trying to flop its way back to the water, but with Lucifer's hook firmly in its tail, death was its only inevitable fate.

The Devil took a step back, pulling his blade away but not lowering it. "Zachariah, is it? Zachariah… you must not be very important. The name isn't ringing a bell."

The angel's cheeks flushed red with fury, which only made Lucifer smile wider. He gave it a minute, before exclaiming,

"Oh, wait… wait, it's coming back to me. You're one of Michael's fanboys, aren't you? Tell me, how is my dear big brother these days?"

Zachariah jerked against the power holding him to the wall, snarling, "You're joking, right? Michael's been dead five, six years now. Everyone knows that!"

Hmm. Lucifer twirled his finger in a lazy circle so that Zachariah's grace was pulled into an agonizing knot, finally succeeding in ripping a tortured scream from the angel. The celestial voice rocked the cavern they were in, making the walls shudder and crumble, but Lucifer ignored this until Zachariah had to stop shrieking long enough to breathe.

Only then did he release the angel fully, allowing his captive to collapse down to the cave floor. Zachariah struggled to get his hands and knees under him, trembling and moaning with pain. Lucifer squatted in front of the angel, once again gripping his chin in a cruel hand.

"What else does everyone know?" he asked with the same nonchalance.

"Y-you don't scare me," Zachariah whined, and this time his doubt and denial rang out clearly amid a delicious flavoring of fear. "Like I said… Lucifer couldn't hack it. I was there, I saw him die."

"Yet here I am. So how about it, Zachariah? You gonna help me out here, or what?"

"No…"

"Ah ah, the word you're looking for is _yes_. See, I've got some questions. About this world, about the archangels, about everything that's happened here. And you," he added, tracing a delicate line of blood across Zachariah's throat, "are going to tell me everything."

"Please-"

"And we're gonna be great friends, aren't we, Zachariah?"

"I- I'm not telling you anything!"

Lucifer's grip hardened, along with his malice. His own red-eyed smile reflected back at him in the wide, shining terror of Zachariah's gaze. The Devil leaned in close.

"Oh, yes," he whispered into the angel's ear. "Yes, you are."


	6. And We'll Teach Them How to War

**Chapter 6 - And We'll Teach Them How to War**

Castiel stood at one of the bookcases, roving his gaze over the spines and familiar titles. It was strange, how so much could be different between realities, and yet some things the same. His eyes caught on one paperback more crinkled than the others, suggesting it had been read multiple times. He reached up to carefully slide it off the shelf. _Good Omens_. Castiel furrowed his brow. So his counterpart had spent time in this room, reading that book? In between serving under Gabriel's command of a flight of angels…it was mind-boggling.

So much about this world was. Including the news about sigils being inert in this reality. That was a reeling blow, and felt like the final nail in the coffin Castiel had built for himself, and unwittingly dragged Mary into as well.

His shoulders slumped as he turned to face her sitting where he'd been on the couch earlier, with her arms across her thighs, fingers wringing together. Gabriel had offered to let them stay, join his unit. It was probably their best option, rather than trying to brave the desolate world outside on their own when they knew nothing about it.

Still, Mary had never wanted such a life for herself or her family, and Castiel couldn't ask it of her.

He cleared his throat. "Perhaps Gabriel can take you to a human settlement. One that's safe." Castiel grimaced as he realized what he'd said; 'safe' was probably as non-existent as sigils in this universe. But Gabriel had said his cohort worked to protect humans, so surely there had to be some places for them to live and survive.

Mary looked up. "And what about you?"

Castiel faltered. "Well, I would stay, aid in the fight as much as I can." He knew he was at a severe disadvantage, practically a liability after Gabriel's verbal thrashing over the state of his grace, but that didn't mean he wouldn't try. And since he'd had a hand in bringing Lucifer over here, it was only right that he assist them in defeating the Devil, even if meant sacrificing himself.

Mary shook her head. "I'm a hunter. I might as well stay and fight, too."

"This isn't your fight, Mary," Castiel protested. "I would never ask you to—"

"You're staying, so am I," she interrupted, rising to her feet staunchly. "Someone has to look after you."

Castiel rolled his eyes in exasperation. Dean really did take after his mother.

"Besides," she went on. "I haven't given up on Sam and Dean because I know they won't give up on us. Sigils work on their end, right?"

Castiel canted his head in acknowledgement. "Right." The brothers weren't as versed in them, but they could be quite dogged in their attempts to figure it out. Still, it could take weeks, likely months…or longer. Castiel and Mary really would have to adjust to this new world for the time being.

Mary gave a decisive nod. "Then we stick together. Because when they do find a way to bring us back, I'm not leaving without you."

Castiel felt a prickle of exasperation with this woman, reminded once again of an obstinate Dean, standing in the middle of a world just as bleak and treacherous as this one. But this time, along with Castiel's determination to get Mary home if at all possible…he wasn't intending to stay behind.

Again, if at all possible.

Meanwhile… Castiel's gaze briefly dropped to the book still in his hand. He was familiar with it, due to Metatron, but perhaps he would read it for himself. Perhaps it would give him insight into that other version of himself. He slipped it into the inside fold of his coat.

Heavy boots echoed from the other room, and Castiel looked over as an angel other than Gabriel entered. His heart leaped into his throat. _Balthazar_.

The angel wore the same vessel—bloodlines of true vessels apparently didn't change between realities—but was dressed in the same leather uniform as Gabriel. With two guns on either hip and his jacket buttoned all the way up to the collar, he looked nothing like the suave and blithe Balthazar of Castiel's world.

For a long moment, they simply stared at each other, and then Castiel couldn't prevent himself from moving forward and throwing his arms around his brother. This wasn't his Balthazar—which was probably a good thing—but the only thing Castiel could think of was the heinous atrocity he'd committed against the brother he loved, all from a dark and downward spiral in the name of the Good Fight. And to see him again, even another version of him…Castiel squeezed his eyes closed against an overwhelming surge of emotion.

Balthazar grunted, not returning the embrace, and Castiel sheepishly pulled back.

"Sorry. I just…"

Balthazar's shrewd eyes maintained a level of strict detachment. "Yes, apparently I'm dead in your world." He roved his gaze up and down Castiel. "Gabriel told me you weren't…him."

Castiel couldn't help but feel as though he'd just been sized up and found woefully wanting. But then, he already knew he could not compare to a version of himself who had not managed to ruin everything ten times over.

Balthazar huffed. "You don't even look like him. Aside from the vessel."

Castiel glanced down at himself, then at Balthazar's attire, which seemed to be what all of Gabriel's soldiers wore. Curious.

"We had…very different paths." Castiel gave a hesitant smile. "I am really glad to see you, though."

Castiel wondered who else was still alive in this reality. So many of his brothers and sisters had died in the wars. Many at Castiel's own hand. It idly occurred to him that meant even angels who had been enemies might still be alive in this universe as well. His throat tightened as he thought of Metatron or Naomi. He almost asked, but it likely didn't matter. With the way things looked outside, Castiel doubted either of them were in a position to be ruling Heaven anytime soon.

Balthazar flicked a curious look at Mary, standing just a couple of feet behind Castiel.

"Oh, this is Mary Winchester," he introduced. "Mary, this is Balthazar."

"Hello," Mary said.

"Charmed," Balthazar replied offhandedly. He returned his considering gaze to Castiel again. "I also hear you're thinking of joining Gabriel's little brigade?"

Castiel couldn't tell whether Balthazar was unhappy about that or not. This version was very difficult to read. "Yes," he said, shifting his weight uncertainly. "Even in my world, I'm still a soldier, and I'd like to do what I can."

Balthazar's gaze narrowed a fraction, and Castiel tried not to flinch. He imagined what Balthazar and Gabriel wanted him to do was not be here. For their Castiel to be returned to them.

That was beyond all their power.

"Well," Balthazar said stiffly. "Guess I should give you the tour, then." He turned on his heel and strode back out the door, leaving Castiel and Mary with nothing but the assumption that they should follow.

And so they did, finally getting a look at the rest of the safe house they'd been taking shelter in. The first outer room surprisingly had six cots, three lined up against opposite walls.

"Do you house other humans here?" Castiel asked.

Balthazar cast a quirked look over his shoulder, then at the beds. "Oh, no. This is our infirmary." He paused. "I suppose you could sleep in here, though," he directed to Mary. He drew to a stop again and furrowed his brow. "Hm, you'll need sustenance as well. I'll ask Jophiel about retrieving some stores."

Castiel tried to place that name, but all he came up with was a brief mention of one of Raphael's supporters. How strange, to think he was here now and serving under Gabriel.

"Thanks," Mary responded. "How do the humans provide for themselves?"

Balthazar shrugged. "I assume they raid stores that are still standing. American consumerism: best preparation for an apocalypse. Those canned goods last for, what is it, twenty years?"

Mary arched a surprised brow.

"And the wine," Balthazar went on. "That just gets better with age anyway."

Castiel couldn't help the corner of his mouth tugging upward. Some things were comforting in their consistency.

Balthazar led them into another room, this one much larger that looked like a command center. There was a huge metal table set in the middle of the floor-plan, with a series of maps and diagrams that had various colored pins stuck in them spread all over it. The walls were covered with mounted rifles and automatic weapons. In one corner, two angels sat around a squat table, glowing beads of light compressed between their palms.

"What are they doing?" Mary asked quietly.

"Restocking our supplies," Balthazar replied.

It took Castiel a moment to realize that what they were actually doing was drawing minute threads of ethereal compounds from that other plane and subjecting it to the kind of grace pressure required to forge angel blades. Except in this case, they were making something else.

The light in one angel's hands popped and fizzled before winking out, and then he dropped a silver bullet on the table. Then he twirled his wrist to siphon off another piece of liquid ether to repeat the process all over again. Castiel had never seen anything like it.

"What is all this?" he asked.

"Welcome to the Resistance," Balthazar replied.

Castiel roved his gaze around, and spotted another doorway across the room. Through it, he could make out angels sparring. "And Gabriel put this together?" he asked dubiously. Gabriel, the one archangel who never wanted to fight his brothers, who ran away to become a pagan… Whereas this looked like a well-oiled operation.

Castiel wondered if their Apocalypse might have gone differently had their Gabriel gotten involved like this.

Balthazar folded his arms across his chest, looking almost defensive at Castiel's skeptical tone. "He did. You- Castiel," he corrected, "was one of his first recruits. Gabriel saved him from being torn apart by demons when his garrison abandoned him to save their own lives."

Castiel's mouth thinned ruefully. He envied his counterpart for having a brother who actually came to his rescue. "And you?"

"I joined later."

Castiel noticed that the two angels in the corner had stopped making bullets, and were now staring at him warily. He tried not to fidget under their suspicious gazes laced with flickers of grief.

"How many are in your flight?" he asked, amazed by everything.

"Twelve—" Balthazar cut off, expression darkening. "I mean eleven."

Castiel internally winced. He didn't know how to say he was sorry for their loss in this situation. He imagined that being trapped here _with_ his counterpart still alive would have been even more awkward and disconcerting. But it was also strange, witnessing their grief for him…but not him.

Maybe it wasn't a good idea for him to stay after all…

"I'm sorry," he said weakly. "I know this is…unusual." That was a woefully insufficient word for it.

Balthazar snorted. "Imagine my showing up in your world."

Castiel grimaced. Sam and Dean would not have appreciated that…though Castiel was grateful just to see his brother again after all this time, in any incarnation. But if the pain had been fresh…he wasn't sure how he would be feeling.

He also suddenly felt self-conscious of what this Balthazar and Gabriel would think of him if they'd shown up in his reality at any point in the past six years. The thought was…not flattering.

Balthazar shook his head and made a strained noise in the back of his throat. "We don't even have anything for the wall."

"The what?"

Grief flashed darkly in Balthazar's eyes again, and he thrust his chin toward one of the far walls. Castiel followed his gaze, squinting at the objects nailed into the concrete. Not weapons, but…trinkets. He stiffened. There were feathers, individual ones strung on silver chains and hanging on the wall. In the middle of some of the necklace V's, small items were also mounted. For a moment, Castiel was afraid that in this world, they kept trophies of their kills.

But then Mary's soft voice broke through his rattled thoughts. "It's a memorial, isn't it?"

Balthazar nodded stiffly. "We've lost a lot of good soldiers—good friends—in this war."

Castiel's chest constricted. He could see now that each feather shimmered with a glossy coating of grace to preserve them. There were different colors in the vanes, iridescent rivulets that marked each individual angel like a fingerprint. If Castiel were to walk over there and touch one, he would probably be able to find out whose it was.

He couldn't bring himself to do that, though. He couldn't even offer a feather as proxy, because his wings were so damaged that it would dishonor the memory of their own brave soldier.

"So, C- what do you think? We're small in number, but effective."

Castiel gave Balthazar a sympathetic look. "If it makes things easier," he started, "you can call me 'Cas.'"

Balthazar eyed him for a moment, then gave a flippant shrug. "Sure, why not. Anyway, like I said, we do what we can to fight demons and angels, save some humans while we're at it. Still interested in signing on?"

"Wait, you're fighting other angels?" Castiel interrupted. "I thought this was a special unit."

Balthazar barked out a laugh. "Special unit? There aren't any units in Heaven at all."

Castiel blinked at him. "But, the war…?"

"Heaven's armies are basically fighting against demons however they want," Balthazar explained. "Raphael's a nut job and has no control over them. At this point, everyone's so disillusioned over the failed prize fight and promised paradise that they're taking it out on any living creature they can find."

Mary cleared her throat softly. "Then how do you plan to win the war?"

"We can't," Gabriel's voice sounded from the sparring room as he stepped inside, followed by four other angels, each of whom were casting a mixture of bewildered and suspicious glares at Castiel.

Mary turned to face him, brow furrowing. "I don't understand. Then what is all this?" She gestured at the elaborate war time setup.

"Just because we can't win doesn't mean we don't fight," Gabriel replied. "And we will keep fighting. Till every last one of us has gone up in a blazing supernova."

There were solemn nods and shared murmurs of agreement from the other angels, which stunned Castiel. It was just the kind of stance he would take—had taken—choosing to stand and fight in a losing war, because it was the right thing to do. There had been too few angels in his world who also believed in that.

Few here, too, it seemed. But some. And Castiel felt himself inspired by their strength of will. It almost felt like…coming home. Or at least to a home that had never really existed, but that he'd always yearned for.

Castiel lifted his chin. "How can we help?"

SPN SPN SPN

Lucifer turned away from what was left of Zachariah. Wing prints decorated the rock face of the wall, burned into the cold stone. Other pieces littered the cave floor, still streaked with hot, sticky blood. Zachariah had been quite informative and eager to provide all kinds of answers, in spite of his insistence otherwise.

So… the fight hadn't gone as planned. Lucifer scowled in derision that his counterpart hadn't managed to put Michael in his place. At least this wasn't a world of fat, stupid humans living in a pampered paradise.

The war didn't bother Lucifer in the slightest—for one thing, it wasn't his problem. He wouldn't be there long enough to participate anyway. Still, it wouldn't have made a bad vacation getaway, except for the demons seemed to have turned into mindless, untrainable attack dogs instead of brutes that he could command. Lucifer would have to exterminate the lot of them and start from scratch, which he didn't have the patience for at the moment.

No, his primary objective was escape. Lucifer's son would be waiting for him. The very _idea_ of those infernal Winchesters anywhere _near_ his child… And that idiot, Castiel, thinking he could keep the Devil away from his own son? Lucifer still planned to kill him for good, if by some miracle he and the woman weren't dead already.

But they weren't his problem any longer.

Lucifer leaned over and wiped the blood from his angel blade onto one of the bigger pieces of Zachariah's body.

"So," he mused to the silent bits of corpse. "Raphael is still alive." But had turned into a madman. Lucifer smiled; finally, a stroke of luck. After all, he was quite the expert at manipulating angels who had lost their minds, what with Michael's insanity in the Cage. Drawing Raphael out and then killing him would be child's play.

What happened to the angels after that was their own problem.

Rage welled up in the Devil yet again, fists clenching so that the air cooled and crackled with the ice and malice in his heart. Soon, he reminded himself. Soon, he would be on his way back to the world he belonged in, back to claim his son.

And when he found those Winchesters…

Lucifer eyed the pieces of Zachariah scattered and splattered around him.

When he found those Winchesters, he would make them _wish_ for such a merciful end.


	7. Once More Unto the Breach

_A/N: Guys, we're already nearing the finish line! One more chapter after this... Things are about to happen fast! Thanks everyone who's been following this story! ^_^_

* * *

 **Chapter 7 - Once More Unto the Breach**

There was a lot for Castiel and Mary to catch up on in this world, and they spent the next few days getting debriefs on life in the middle of a war-torn Apocalypse. There was also the matter of figuring out just how they might integrate into Gabriel's cohort. Castiel was more than willing to participate in missions, but without his wings, he was more of a burden than valued soldier. He'd need to depend on someone for transportation to and from battles, and that could make him a liability if a hasty exit was needed and someone had to take the time to find and retrieve him.

And then there was Mary, who despite her skill and prowess in a fight, was even more vulnerable.

"Have you ever tried allying with some of the human hunters?" she asked Balthazar as he showed them their maps of enemy strongholds and human settlements.

The angel snorted. "Hunters are a shoot first, don't bother asking questions type of breed."

Mary pursed her mouth. "Well then maybe they need a fellow hunter to build that bridge."

"What would be the point?"

Mary rolled her eyes. "Alliances in a war can make all the difference, and it doesn't matter _who_ they're with. Besides, didn't you say you guys try to protect humans? Might help if they didn't try to shoot you for it."

Balthazar shrugged, but Castiel certainly thought the idea had merit. It might be how he could contribute, as well, if he accompanied Mary to a settlement to make first contact. He could show the humans in this reality that not all angels were the celestial terrors they'd come to see duking it out in the night sky.

The front door banged open as Gabriel strode in like a crackling storm. There was a roiling darkness in his eyes, a tempest of staunchness trying to mask flickers of disturbed agitation.

"Listen up, people," he said loudly. "I just got a report that Mirror Lucifer took out Raphael."

A collective hush fell over the room for a stunned moment.

"What?" someone asked fearfully.

"Does that mean…?"

"Raph was barely an agent of Heaven," Gabriel was quick to reply. "It was not the prize fight." He paused, something haunted flitting across his face. "But apparently Lucifer cut out Raphael's grace and took it."

Castiel furrowed his brow in confusion. Why would Lucifer do that? He had no need to steal another's grace with his own intact.

Horrified outrage erupted from the other angels.

"He wouldn't."

"Is that even possible?"

Gabriel shook his head. "This Luci is apparently more bold than the original." He turned to Castiel. "You know him best; why would he take another archangel's grace?"

Castiel shifted as all eyes turned on him expectantly. "The…only thing I can guess is he's trying to gain enough power to reopen the rift between realities."

"Can he do that?" Mary asked, and Castiel didn't miss the tremulous thread of hope in her voice. If Lucifer were to succeed, they might be able to go home themselves.

But then all of their effort and sacrifice—on both sides—would be for naught if Lucifer was freed yet again.

"We can't allow him to get far enough to try," Castiel said gravely.

The light in Mary's eyes dimmed with the pronouncement, but she nodded solemnly in agreement.

"Why not?" Balthazar spoke up sharply. "Why not let the Devil go back? This world is doomed enough without him mucking things up even worse."

Castiel internally winced. He had played a crucial part in condemning this world, all to save his own. He could understand Balthazar's stance here.

"No," Gabriel said with grim firmness. "I know why Castiel gave his life to bring Lucifer here, and I intend to see his plan through."

Balthazar shot him a dubious look. "Which was what, exactly?"

"To give us a second chance."

Balthazar narrowed his gaze, but then his expression slackened in realization. "You can't be thinking of fighting Lucifer? Michael did and was destroyed!"

"I know," Gabriel said soberly. "But I won't let Castiel's sacrifice be for nothing. He died that we might have a second chance at ending the war. So I am going to finish what he started. For all of you." Gabriel paused, eyes shining. "For him."

The other angels bowed their heads, no whispers of discord or doubt, just solemn mourning and silent fealty.

Castiel suddenly wished he were not here to witness this. This depth of love and devotion these angels held for his counterpart. It was a love he had never experienced in his own world. Oh, Castiel had led, and there had been many who followed. But their allegiance had always been…fickle at best. As far as he knew, he had never been mourned so deeply after his many deaths. Castiel found it difficult to mourn for a version of himself he didn't know personally, but he did mourn what he in his reality never had.

Except…he did have something this other Castiel didn't—Sam and Dean. They cared about him with the fervency and fierceness that these angels held for their lost brother. Sam and Dean called him family. They would mourn him. _Were_ mourning him.

And for a weak moment, Castiel wanted to let Lucifer try to open that rift, because it might give Castiel the chance to go home, to apologize to the Winchesters for running off with Kelly, to return Mary to them as his first offering of penance. He wanted to go home where he was loved, where maybe his failures didn't matter, just like these brothers and sisters didn't blame or hate their Castiel for bringing the Devil down on their heads. Instead, they would fight in his memory.

But Castiel could not be selfish, could not dishonor all the sacrifices that Sam and Dean had already gone through by letting Lucifer threaten them again. And…he would not dishonor his alternate's memory by denying this dying world the chance to save itself. He and Mary would find another way. Or Sam and Dean would. But it would not be through Lucifer.

Balthazar drew his shoulders back. "Then what do we do?"

Gabriel was silent in a moment of contemplation. "We'll have to move quickly. Find Lucifer before he's able to tear a hole in space and time."

"He will probably return to the location of the original rift," Castiel finally spoke up. "That's where his son was last seen, and that's what he wants to get back to more than anything."

Gabriel nodded. "Then that's where we'll go. Suit up, everyone." He started to turn away, but paused and swept his gaze over them again. "No matter what happens, it was an honor serving with you all."

With that, he turned and walked out the door, and Castiel couldn't help but feel the finality in the air. But despite the fact that this wasn't his world, and these weren't the brothers he knew, Castiel did not want to see any of them hurt or killed. He did not want Gabriel to sacrifice himself.

And so Castiel resolved in that moment to do what he could to ensure Gabriel's success in this endeavor. It would not be the first time Castiel had confronted the Devil, and history had taught him that it usually didn't end well for himself. But he refused to let his brother face Lucifer alone. Refused to let him fall.

It was what he would do—in any universe.

SPN SPN SPN

Gabriel's eyes narrowed, too used to the flashing red lightning to be much affected by its constant presence in the darkness. The heated electric streaks arched across the dome of Earth's sky. Though the lightning helped illuminate the barren landscape, neither Gabriel nor his warriors needed it to help them see.

At any rate, it wasn't the only source of light in the wastelands tonight. Even before Gabriel had landed, he could see the other glowing, amorphous blob, and the archangel who held it.

With barely a rustle of his wings, Gabriel touched down directly behind the other Lucifer, followed swiftly by his soldiers. Behind him, he felt the others fanning out to establish a perimeter in case sounds of the fight drew a crowd of either demons or angels. There could be no interference, especially with the rift between worlds.

And speaking of the rift… He studied the shimmering orb Lucifer held; it was grace, and it must have been Raphael's, but it looked… spoiled. It had a blue-green tinge of rancid meat, putrid and festering not unlike the archangel's mind, in the end.

Lovely.

Lucifer's other hand was aglow with power, white-hot and dazzlingly brilliant. He always had shone the brightest in this world, too.

It wasn't enough though, Gabriel realized before he could start to worry they might have been too late. His eyes narrowed, watching without comment as Raphael's grace slowly snaked upwards, revealing a glowing crack of the rift between worlds—but it wasn't opening.

Looked like they'd be having that fight, after all.

Lucifer straightened, head cocking back for a second as though registering that he had an audience. When he turned around, his eyebrows were lifted and his gaze penetrating.

"Gabriel. Well, isn't this a surprise."

All smugness and conceit. Just like the Lucifer that Gabriel had known, just like the Lucifer who had helped ruin everything. Gabriel crossed his arms, feeling the reassuring weight of his pistol at his hip. The bullets wouldn't kill Lucifer, but the urge to empty a magazine into the bastard just on principle was overwhelming. Just to wipe that conceited smirk off his face.

Lucifer's gaze slid to the right and a fraction over his shoulder, taking in the squad positioned all around them. Even Castiel and Mary were there, though currently out of sight. Honestly, this was no place for them, but there'd been no talking the two out of it. And in the end, why not? Death was a reality. It would come for all of them in the end. Might as well let them go out in the manner of their own choosing, and they _had_ brought Lucifer there in the first place.

Lucifer didn't attack, though, merely cast a scornful look at the cadre and shook his head. "Really?" he asked Gabriel. "You a company man now? That's… disappointing."

"I _am_ the company."

The older archangel's sneer twisted all the more as he caught Gabriel's eyes. "You always were full of surprises. You know, in _my_ world, I actually hated having to kill you. You're not like the rest of the panty-waisted whiners in Heaven. Never were. _You_ have something different, Gabriel. Something special."

He gestured at the unforgiving terrain, shaking his head. "Brother, you're wasted here!" Lucifer protested. He took a step towards Gabriel, who didn't budge. "I mean, what are you even doing? A couple of hit and runs on some loser demons, whenever you find some? Is that really what you've been reduced to? It's shameful, Gabriel. You're worthy of so much more."

Was this Lucifer actually trying to charm him? Gabriel stared at the archangel, not saying a word. Lucifer didn't even seem to notice the lack of response, drawing himself up like the puffed up pigeon he'd always been, and extending a hand.

"Come back with me, Gabriel. This place is a dump. In _my_ world, everything— _everything_ —is still ripe for the taking. Trust me, it'll be much more fun on the other side."

"From what I understand," Gabriel retorted coolly, "you pretty much want to replicate this piece of real estate over there."

Lucifer huffed, half turning away before spinning back around. "Seriously?" he demanded. "You're _still_ harping on protecting humanity?"

A thousand and one waspish retorts zinged through Gabriel's mind, but he didn't bother. At least this Lucifer was making it easy for him to remember why he'd never taken sides between the two eldest archangels. Gabriel still hadn't budged, nor had the wary squadron at his back. He could feel the waves of animosity rolling off of Lucifer, though, and could easily pick out the tell-tale signs that he was about to attack.

Raising one shoulder in a lazy shrug, Gabriel replied simply, "Sorta seems like the thing to do, don't it?"

Lucifer shook his head. "Fine," he snarled. "Just as well… looks like I need another archangel's grace to open the portal anyway. Yours will do."

The Devil flung himself at Gabriel, the two archangels colliding with a blast like thunder. Gabriel rolled with the attack, neither of the two bothering with weapons as they threw fists and furious bellows instead.

Damn, the son of a bitch was strong. Gabriel reeled back as the older archangel landed a solid punch to his cheek, sending another crack like thunder rolling unobstructed across the dusty basin. He stumbled, then dropped to the ground and lashed out with a foot instead. Lucifer's legs were swept out from under him. Immediately, Gabriel launched himself on top of the Devil, both fists swinging in rapid succession.

Blood dripped from Lucifer's mouth, but his eyes lit in an eerie red glow. He shouted, a wordless roar of rage. He was too fast, and Gabriel couldn't stop him as the Devil slithered out from under his grasp. Nor could he dodge in time to avoid the brutal kick to the side of his head.

Stars exploded in scintillating sparks, blinding the archangel. Gabriel hit the ground hard and tried to roll up to his feet.

Again… too slow. A hand grabbed him by the collar of his jacket, dragging him backwards a few feet before throwing him with the strength only an archangel could possess. Gabriel slammed into something hard—one of the pillars, he thought—hard enough that stone cracked and crumbled, and he slid down, stunned.

"Gabriel!" one of his troops shouted from close by. "No!"

Gabriel blinked slowly, trying to clear his spotty vision. Through the haze, he saw movement: leather jackets and the flash of guns… heard the crack of gunshots and the echo off the other monoliths… a soft grunt from Lucifer as the useless bullets riddled his body.

His eyes re-focused just in time to see the older archangel whirl on two members of the squad, who were still shooting at will, and raise his hand.

"No…" Gabriel tried to yell; winded as he was, no sound emerged, only his horrified gasp as Lucifer snapped his fingers, wiping out the two angel warriors who had come running in to help. The few remaining soldiers began to scramble for cover while fighting to maintain the perimeter they'd set.

"As for _you_ ," Lucifer snarled, spinning back to Gabriel. An angel blade dropped from his sleeve, and his free hand lashed out to grab a handful of Gabriel's hair. The archangel grimaced and struggled to get loose as Lucifer forced his head back to expose his throat.

Shit. Heavily, Gabriel thanked his lucky stars that at least Anna was still out in the field with her small contingent… she could carry on the mission… at least, for whatever amount of time they had left.

Gabriel didn't close his eyes or look away from Lucifer as the Devil triumphantly thrust the blade towards his throat to slice out his grace. Neither of them noticed Castiel running in from behind. Before Lucifer could ever make the cut, the angel had grabbed him around the middle and tackled him to the ground.

"You putrescent little slug!" Lucifer hissed. He shoved Castiel away from him—who had, _again_ , attacked without any actual weapon that would do a _damn_ thing against an archangel. He couldn't hope to match Lucifer's strength or his rage, could do nothing to defend himself as Lucifer grabbed him and pulled him up to his knees.

Blow after blow rained down on the younger angel, each cruel punch leaving more and more splotches of Castiel's own blood coating his face from Lucifer's knuckles.

But all Gabriel could see was _his_ Castiel, at the end of Lucifer's blade in a strange world. This Castiel's clothes were odd and his eyes had seen a different life, but it was _his_ face Gabriel saw. He needed no other catalyst to surge to his feet and charge.

Gabriel ripped Lucifer away from the angel. _He_ had the advantage now, distracted as the Devil was with his vengeance on Castiel. Pressing that advantage, Gabriel struck with everything he had, punches and gouges and short, sharp jabs. Every trick he'd ever learned as an archangel warrior, plus a few moves he'd stumbled on along the way. It was enough to drive Lucifer away from Castiel and the flickering line of grace that hovered in the air, until finally Gabriel thrust the heel of his boot straight into Lucifer's chest.

The dark archangel stumbled back and landed on his knees, gasping. The angel blade he carried shot up to ward Gabriel off, and Lucifer's free hand twisted in the air to craft a crackling, lethal ball of grace.

"You know," Lucifer snapped as he climbed slowly back to his feet. "I'm surprised at you. But it's no use fighting me, Gabriel. You tried that once… you lost in my world, and you'll lose here, too. And you want to know why?"

"I'm betting you're gonna tell me."

From the corner of his eye, Gabriel saw Mary rush in to kneel at Castiel's side, trying to pull the angel back up to his feet. He couldn't worry about them at the moment though, as he and Lucifer started to circle each other.

"Because I know where your heart truly lies," hissed Lucifer. "Where it's _always_ lied. Because I know what you are: a _coward_. You ran away, too afraid to stand up to your brothers. You play all big and bad, but you don't have it in you to win this fight."

Oh, was that so? Gabriel's eyes narrowed, sinking deeper into his fighting stance. "Well, I don't know about the other me," he snapped. "But _I_ stand by my family."

"Really?" Lucifer shot back as his smile widened but the red glow refused to diminish. "Well, in that case, you should be jumping at the opportunity to join up. After all-" The crimson fire in his eyes flared brighter. "-I _am_ your family. And with Raphael dead, I'm all there is left. I'm your brother."

Gabriel stared at Lucifer, trying to judge if the Devil was just trying to trick him or if some part of the archangel actually _believed_ this delusion. Not that it mattered either way. Snorting, Gabriel shook his head, voice dropping ten degrees as he snapped,

"No. You're not." His eyes flicked to Castiel, then returned to Lucifer. "You _killed_ my brother."

Nothing could ever redeem Lucifer from that. If they were the only two beings left in all creation, Gabriel would still put a bullet through the Devil's heart and call it a damn good day. Lucifer had murdered Castiel, the fiercest warrior with the truest, most hopeful heart of them all. If anyone had deserved to survive this war and find some kind of paradise, it had been Castiel.

….And how _dare_ Lucifer think he could just take Castiel from them and get away with it?

Gabriel's unseen wings rippled with power and sudden decisiveness. Turning his back on Lucifer, the archangel shot his hand out towards the portal where Raphael's grace was still simmering, still activated through Lucifer's own grace. If a third source was what it needed, a third source was what it could have.

The glowing orb of molten gold streamed into the crack between the worlds. With a low whoosh, the portal opened, sending a blast of wind over the company.

"Castiel, you and Mary go!" Gabriel shouted, looking down at the blood-stained face of his brother.

Castiel hesitated, expression anxious. Still more worried about Lucifer than saving himself. Damn, that was just like him. Gabriel gave him a nod, measured and calm.

"Go," he commanded, softer. Maybe it wasn't _his_ Castiel… but he still wanted the angel to have the life he deserved, the life his Castiel couldn't have. And that wasn't here.

Gabriel couldn't replace his Castiel; he could only avenge him.

"No!" Lucifer snarled, surging forward, only to be met with Gabriel's powerful form blocking his way, holding him bodily back from the portal. " _NO!_ "

From the corner of his eye, Gabriel saw Balthazar rush in to help Castiel back up to his feet and push him and Mary towards the rift.

"Go!" Balthazar urged, herding the two along.

Lucifer was shouting again, straining against Gabriel as Castiel and Mary stepped through the portal and disappeared to the other side. He couldn't break free though, couldn't fight through to stop the two, or to prevent Balthazar from closing the rift behind them and destroying what remained of Raphael's grace.

Without the power source, the crack in space and time sputtered, then died. Even if Lucifer killed Gabriel now, it would do no good; there wasn't enough grace to re-open the rift. Lucifer was trapped, forever.

How was that for a little poetic justice?

Releasing Lucifer, letting the archangel fly back to where the rift had been moments before, Gabriel flexed his wings. His brother had bought this chance for them with his life, and that opportunity would not be thrown away. It was time to end this.

For Castiel.

Lucifer turned on the spot, murderous, uncontrolled madness in his features. Gabriel smiled, grim and cold, as he prepared for battle. Let the Devil come; he was ready.

"Let's dance."


	8. Dear Friends, Once More

_A/N: Thank you to our anonymous reader Zev for your review! I can't wait until Cas's character arc brings him to a point where he knows his own self-worth and has found peace and happiness. He deserves it. Confident and badass Cas will always be awesome! :D_

 _Thank you so much, everyone who's joined us on this adventure! Aini and I both deeply appreciate the support for this experimental collab and will see you again soon! (Aini sooner, haha, she'll be posting regularly through the summer)._

 _Please enjoy the conclusion, and thank you in advance to any anonymous reviewers ^_^_

* * *

 **Chapter 8 - Dear Friends, Once More**

Mary and Castiel tumbled out the other side of the portal, and both nearly pitched forward onto the ground, but the fact that they were gripping each other tightly somehow managed to save them from the fall. There was a 'brrp' and pop, and they both spun around as the glowing rift zipped shut and winked out before anyone else could follow them through.

She blinked in the sudden daylight, an afternoon sun burning brightly in a blue sky. The tranquil lake ebbed and flowed against the shore, and sentinel pines rose up out of the ground rather than blood-tinged monoliths. They were actually home.

Mary's heart was pounding so fiercely with adrenaline from the fight, that the only thing she could focus on at that moment was breathing in and out. She almost couldn't believe it. She had only just begun to resign herself to their situation, despite her faith in her boys relentlessly looking for her. To be back so soon…it was like whiplash.

She looked at Castiel, who was gazing morosely at the space where the portal had been. She wondered if those other angels really had a shot against Lucifer. She hoped so.

Mary put a hand on Cas's shoulder, drawing his gaze. "Come on, let's go home." Maybe get him cleaned up first, though the abrasions on his face already seemed to be healing faster than injuries dealt by a blade.

With a solemn nod, Castiel turned to head back toward the house, but paused and quirked a confused look at a tarp that had been spread flat over the ground right behind them. Mary's gut tightened; she knew what it was covering.

She was filled with a sudden urge to find her boys as quickly as possible. She could only imagine how wrecked they must be, and hoped they hadn't done anything stupid.

Yet when she and Cas made their way around to the driveway in search of a vehicle, they both paused in surprise to find the Impala still parked there. Were Sam and Dean still here? Or…or had something happened to them after Mary fell through the rift with Lucifer? There had still been the nephilim about to be born, and she knew how worried her boys were that it would turn out to be something dangerous.

Her nerves started firing with anxiety and adrenaline again as she headed for the front door, Cas right behind her. It wasn't locked, just as it hadn't been that night…what was it, a week ago? It felt longer, being trapped in that nightmare world. It must have been equally torturous for her boys.

Mary pushed the door open and stepped inside. At first, the place seemed quiet, maybe empty, but then she heard shuffling and clinks coming from the kitchen. Not sure what she was walking into, Mary nevertheless closed the distance to the kitchen, only to stop in the entry when she found Sam cleaning up a bunch of empty beer bottles.

Relief flooded through her. "Sam."

He jolted upright, eyes flying wide. "Mom?" he asked, voice cracking on disbelief and hope, and she could have wept at it. "Are you- how did you?" Sam sputtered, finally casting the bottles on the table with a clatter and sweeping around to wrap her in a ginormous hug.

Mary lifted her arms to squeeze back as hard as she could. "It's a long story."

Sam suddenly stiffened and jerked back. "Lucifer?"

"Gone," she replied. "For good."

Some of Sam's shock started to bleed into giddiness. "I can't believe it. We thought that…" He trailed off, obviously not wanting to say that they'd thought she was dead.

Speaking of which. Mary turned to glance over her shoulder in search of Cas, and found him hesitating at the corner, as though he didn't want to disrupt their reunion. Did the idiot still not get that he was part of this family unit too?

Sam followed her gaze, and Mary heard him suck in a sharp breath. " _Cas_?"

"Hello, Sam."

Sam took a step toward the angel, then paused, a slack-jawed smile washing across his face. "Wait, did Chuck bring you both back?"

"No," Cas replied, rolling his shoulder awkwardly. "As Mary said, it's a long story. I was trapped in the alternate reality with her."

"What?" Sam's brows knitted together. "But…we saw you die. Lucifer—" He choked off, eyes squinting against a glint of moisture, before they widened again and he shot Mary a horrified look. "You didn't bring the Cas from _that_ reality back, did you?"

"No, it really is me, Sam," Cas interjected. "The- the Castiel that Lucifer killed was from that other world."

Sam just stared at him. "What- how?"

"Again, it's a long story," Cas said sheepishly. "And Dean should be here for it—"

"Dean!" Sam suddenly yelled, making Mary wince. "Dean, get down here!" He then moved forward and pulled Castiel into a hug.

"God, Cas," Sam let out in a shuddering breath. "I don't care. You're back; that's all that matters."

Castiel closed his eyes and returned the embrace.

Mary looked up as heavy footsteps came lumbering down the stairs, bringing her eldest with mussed hair and bloodshot eyes.

Dean barreled into the room, looking half awake and hungover. "What? What's wrong?" He froze when he saw them, expression shifting between shock, desperate hope, and paralyzing fear as though he doubted what he was seeing was real. "Cas?" he whispered.

Sam stepped back from the angel, and Castiel turned to give Dean an apologetic look.

"Hello, Dean. It really is me. There was—"

Once again, he was not allowed to finish as Dean surged forward and enveloped him in a crushing hug. Mary wasn't sure who was holding on tighter at that point, and she felt her eyes growing watery. For the first time since she'd been resurrected—maybe the first time in her life—she'd finally been able to give her son something he needed more than anything.

Dean's eyes found hers over Cas's shoulder, and his were just as wet, drowning in sheer relief and gratitude and love. She reached out to clasp his hand where it was half fisted in Castiel's coat. He squeezed back.

Sam put his arm around her shoulders, enfolding them all in one big embrace. Just like when she'd found her way back to them before, only now she saw how something crucial had been missing then. But not anymore.

She knew there was a lot to explain, a lot to catch up on. About Kelly and the child, about what exactly had happened in that alternate universe. But right now, all Mary wanted was this moment, her family complete and back together. _All_ of them.

SPN SPN SPN

Castiel stood at the foot of the grave, eyes fixed on the small marker the Winchesters had left there for his counterpart - for _him_. It wasn't much, just a stone with a roughly etched cross, yet Castiel could envision either Dean or Sam carefully scoring the lines into it and reverently placing the rock over the mound of earth that they'd laid his empty vessel to rest in.

Of all the times Castiel had died before, there had never...never been anything left behind to bury. He wondered whether some form of his alternate was still out there somewhere, or whether an angel's death was truly as permanent as he and his brethren had always assumed. Was it egotistical to believe that that version of himself had deserved some sort of paradise?

Either way, his memory would live on, and hopefully his legacy, in what his death had bought. Castiel thought about Gabriel and the other angels, wondering how they had fared in the battle, hoping they had survived. He would probably never know for sure… but in his heart, he believed they would.

Reaching into an inner pocket of his coat, Castiel pulled out the book that he had taken from the tiny bookshelf in that other world. The weathered copy of _Good Omens_ was a little rough, a little worn from use, but somehow that was fitting. Castiel eyed the book, then slowly knelt to set it next to the stone.

"I'm sorry," he said out loud, though it was unlikely the words would be heard by anyone but himself. "I wish there had been something to hang on the wall. Something to commemorate you with. But, for whatever it's worth… your family will be alright. I have faith in that. And I don't believe they need any trinkets to remember you and… and what you meant to them."

Castiel closed his eyes, contemplating the other angels' grief and how Sam and Dean might have been similarly grieving. His chest tightened to imagine his friends in so much pain. For several moments, he remained still, before finally heaving a sigh and climbing back to his feet. When he turned, he startled to find Dean standing a few feet away, watching.

"I thought it was you," the Winchester said in a subdued tone.

Castiel ducked his gaze. "I know. I'm sorry."

"Don't- don't apologize for being dead. Or not dead." Dean looked away for a moment, rubbing a hand down his face. When he turned back, there was a sheen in his eyes. "I couldn't even do it."

Castiel frowned, not understanding.

Dean gestured toward the grave. "Sam had to. And you deserved a hunter's pyre, but I just couldn't live with…" His voice broke.

Castiel ached to hear the same pain he'd heard in Gabriel's voice now so audible in Dean's. He shook his head, and took the few steps to reach out and clasp his friend's shoulder. The angel wished he knew what to say to ease the burden Dean seemed insistent on carrying.

"You have nothing to feel guilty for." If anyone was to blame, it was himself.

"I couldn't even come out here and honor you like you deserved."

Castiel lowered his head. "I know we were on strained terms…"

" _No_. No, Cas, that wasn't- after Lucifer and you and Amara, I thought things were finally going to be good. And then that night in that barn with Ramiel...I almost lost everything, _again_. And we got our Hail Mary save, again. And then you disappeared for weeks, only to find you were in Heaven. And the thing with the Colt-"

"I know-"

Dean barreled over him, "And we lost you again when that baby-God pulled some sort of crap. So yes, I was pissed, because we were losing you all over again after fighting so hard to save you. I'm never able to _save_ you."

Castiel opened his mouth, his first instinct to assure Dean that it wasn't his job to save him, but then he thought better of it. Although he still—and would always—consider himself a guardian to the Winchesters, the truth was that it had been working both ways for longer than Castiel had realized. The same closeness he'd seen among the angels in that other reality… he had that, too. Right here.

He remembered how wistful he'd felt at first seeing his alternate self with his grace fully intact, his wings as strong as ever, but Castiel knew in his heart that given the chance, he wouldn't have traded the Winchesters for that. They were his choice. They kept him… well, not human, but they kept him himself.

"You did save me," he whispered. "So many times, Dean. When I doubted, when I was an outcast from Heaven. I told you that the things we've shared together have changed me. They rescued me from a life of...apathy. And blind devotion." Castiel hadn't had Gabriel in this world to save him, to help him find a purpose to fight for. Dean had done that.

And as for blind devotion...Castiel now saw that Dean was right. Something had happened in the playground the night the unborn nephilim had helped him kill Dagon. He wasn't entirely sure what, didn't know how to make up for abandoning the Winchesters like he had. But that...tether, or whatever it had been, was gone now. Perhaps severed by his time away in the alternate reality, perhaps only once Jack had been born. Either way, Castiel no longer had that subversive drive urging him down such a path.

"Dean," Castiel spoke up again hesitantly. "About Jack- about the nephilim."

The hunter looked up at him, an understandable wariness in his features. "Yeah?"

"We need to find him. But," he quickly added when Dean shifted, "not because… I mean, he's going to be unimaginably powerful. Now he's out there, and it's… my fault. Taking Kelly, leaving you-" How was a simple apology supposed to cover this? Castiel shook his head, momentarily overwhelmed. "I should have- I mean, I never…"

Dean was still watching him, some of the tension loosening. He took a breath, then pointed out, "Yeah, we need to find him. Sammy's been working on it. But it's not your fault."

"I left you there. I turned my back on you in favor of him."

"I know that wasn't you."

Castiel's jaw ticked in frustration. Maybe not completely, but it _had_ still been him.

"Look, man," Dean went on with a shrug. "Whatever was going on, whatever wasn't going on, I don't know. But no matter what, you don't have to apologize. Let's just enjoy the fact that you're here, okay? That's all I care about."

In that moment, it was all Castiel wanted to savor, too.

"So… what now?" he asked.

Dean straightened and gestured back towards the house. "Now we have work to do. You with us?"

Castiel smiled. "Always."

He cast one last look at the grave that'd been meant for him, but mercifully had not come to pass. He was loved. And he was home. And together, they would face this potential threat. Together, they would venture once more into the breach.


End file.
